Lasiocampidae

The Lasiocampidae are reasonably diverse in the Old World tropics, less so in the new. They have moderate representation in the Holartic and Australasia,  but are not represented east of Papua New Guinea. They are generally large species with deep forewings, and hindwings at least two thirds of the area of the forewing, often rounded; however there are several genera in Africa and the Indo-Australian tropics where the forewings are narrow, apically produced, and the hindwings relatively much smaller, the abdomen protruding well beyond them. These have been suggested in the introductory section to fill the niche occupied in the Neotropics by similarly Saturniidae. Sexual dimorphism is usually marked.

Adults

The tongue is vestigial or absent. The male antennae are strongly bipectinate, though this is sometimes reduced over the distal portion; those of the female are usually less so. The frenulum is absent, the humeral lobe of the hindwing being expanded and often containing humeral veins. Patterning on the hindwing is costal (dorsal or complete in other bombycoids).

In the forewing venation R2 and R3 have an common stalk, as do R.5 and M1, usually with R4 branching off from this stalk more basally and anteriorly. A few Oriental taxa have the latter triplet with R4 and R5 bifurcating distally, with M1 arising more basally and posteriorly as in the Mimallonidae (see Fig. 2). The anterior cubital vein in both wings is strong with its two branches and M2 and M3 arising from it in a quadrifid array. On the hindwing Sc and Rs anastomose for a short distance subbasally, forming a basal or humeral cell anterior to the main cell (Fig. 3). This basal cell becomes considerably expanded in the Gastropachinae (Fig.3).

In the male genitalia the saccus is often associated with a complex plate or two elongate arms that usurp the function of  the rather reduced valves; this structure was termed the cubile by Lajonquiere (1968). The aedeagus is often short, sometimes with a ventral spur, and the vesica is frequently scobinate. The uncus is reduced, the gnathus lost, and  the tegumen often weak except in one subfamily restricted to the New World (see below).**

Larvae

The larvae are densely invested with secondary setae and appear very hairy. They are cylindrical or rather flattened, usually with lateral lappets or protruberances below the line of the spiracles on each segment, the prothorax having a second protruberance above the first. In many genera there are also transverse saddles of densely packed short setae dorsally on T2 and T3 (see Plate 19; Gastropacha pardale Walker). If one attempts to pick a larva up, the dorsal part of the thorax is brought strongly back against the hand (or attacker), leaving the short setae of the thoracic saddles embedded in it (Tho Yow Pong, pers. comm.). The cocoon is well developed.

Subfamilies, and groupings of Oriental genera

Franclemont (1973) reviewed the subfamilial classification, recognising three subfamilies in the New World. The Macromphaliinae may wellbe restricted to that region, and appear somewhat plesiomorphic in male genitalia characters: the uncus, gnathus or socii are usually present, and there is no cubile. There are three small Africa subfamilies, Chondrosteginae, Chionopsychinae and Archaeopachinae, and a fourth, Gonometinae, that Franclemont suggested might be included in the Gastropachinae. The Gastropachinae and Lasiocampinae are the other two New World subfamilies and occur worldwide. Only these two are represented in the Oriental fauna, and their validity needs investigation.

The Gastropachinae are defined by massive expansion of the humeral cell and the presence of  a sequence of humeral veins arising from Sc on its anterior margin (Fig. 3). Yet the presence of a cubile and the double structure  of the ante- and postmedial fasciae of the forewing suggest they may represent just a section of a grouping within the Lasiocampinae.

The genera discussed first in the systematic section all have long, rather slender cubile arms; amongst them are the taxa with the most extreme development of the narrow forewing and reduced hindwing. Paraleda and Streblote appear to have single fasciae, those of the rest and the Gastropachinae being double. The Gastropachinae, Bhima, Metanastria and Lebeda have the discal spot between the doubled fasciae; in Suana and Kunugia it is more basal, between the antemedials, and it Lajonquierea, with a very short cell, it is even more basal still. Apart from the Gastropachinae none of these genera has humeral veins. Thoracic larval saddles tend to be well developed in these genera, but not in the few instances where larvae of the next group are known.

Single fasciae occur in all the genera from Arguda to Trabala in the systematic section. The cubile is broad, not divided into arms in most genera, reduced in some, absent in Trabala. Some have one or two humeral veins, but these arise from the base of the humeral cell and are connate when there is more than one (Fig. 3). The small complex of genera with mimallonoid venation (p. 11) has such humeral veins.

Host-plant preferences

Most Lasiocampidae are polyphagous, the 12 plant families most frequently noted being listed in Table 4. Leguminosae and Myrtaceae are most often utilised. 27 other families have been recorded once or twice as lasiocampid host-plants in the region: Anacardiaceae, Annonaceae, Barringtoniaceae, Bischofiaceae, Bombacaceae Capparidaceae, Casuarinaceae, Combretaceae, Elaeocarpaceae, Flacourtiaceae, Geraniaceae, Gramineae, Guttiferae, Lythraceae, Melastomataceae, Meliaceae, Moraceae, Myrsinaceae, Naucleaceae, Polygonaceae, Punicaceae, Rhamnaceae, Sapindaceae,  Sonneratiaceae, Sterculiaceae, Tamaricaceae, Urticaceae, and the conifer families Cupressaceae and Pinaceae.**

Geography and habitat preference

Of the 60 species known from Borneo, 18 are endemic, 31 Sundanian, three Sundanian and also recorded from S. China (Metanastria gemella, Syrastrena sumatrana, Trabala pallida), four are from the N.E. Himalaya and Sundaland, and the remaining four are widespread in the Oriental tropics.

The genus Lajonquierea is purely Sundanian, and Arguda, Radhica, Radhica, Syrastrena, Trabala and Micropacha are most diverse in Sundaland. Chonopla extends north to Burma. Most of the other genera are widespread in the Oriental tropics, Euthrix being also widespread in the Palaearctic and Gastropacha similarly, though also represented in Africa. Streblote is predominantly Africa, reaching its most easterly limits in Borneo and the Philippines. The genera Bhima and Takanea are unusual in being predominantly subtropical, with one outlying species in Borneo or Sundaland.

To the east, Sulawesi has a highly endemic fauna, with single species of Lebeda, Paralebeda, Suana, Hallicarnia, Odonestis and Trabala, and two of Kunugia. The only non-endemic is a Gastropacha species that also occurs on the Philippines and in mainland Asia but has not been recorded from Borneo.

In tropical Australasia, particularly Papua New Guinea, there are taxa of Oriental affinity such as Cyclophragma  (cf. Kunugia), Pseudophyllodes (cf. Suana), Pararguda (cf. Arguda) and two genera in the Gastropacha group. In Australia there is an endemic group that does not appear to have close affinities with the Oriental fauna. The family does not occur from the Solomons eastwards.

15 species have only been taken in montane forests, two, Paradoxopla cardinalis and Trabala rotundata, only from G. Kinabalu. 30 have only been taken in the lowlands, and one of these, Streblote helpsi, appear to be restricted to coastal habitats. The remaining 15 have been taken over a range of altitudes.

Systematic account

The order of genera follows the currently accepted higher classification, Lasiocampinae followed by Gastropachinae. The quadrifasciate Lasiocampinae with a strong cubile are treated first, followed by the bifasciate genera where the cubile is weak or absent.