116 BRITISH LEPIDOPTERA. 



several days. Of the larval habits of D. pini, Fletcher notes (Entom., 

 xxxiv., p. 198) that the larvae occur in thousands at Wei-hai-wei, 

 on fir-trees, in May, and are fullfed about the middle of June. The 

 larvae occur in two distinct shades — orange and grey. When annoyed 

 they eject a clear watery liquid, and curl their heads down, thus 

 prominently exposing the big, blue, hairy tufts, composed of short 

 easily-detachable bristles. If further annoyed, they lash about with 

 the fore-part of the body and try to bring these tufts into contact with 

 the aggressor, and one left a number of short blue hairs embedded in 

 Fletcher's skin. These hairs are also woven in the texture of the cocoon 

 so as to form a regular chevaux-de-frise, they are not easily extracted 

 from the skin, but break off, leaving the points embedded and would, 

 no doubt, prove highly urticative to persons with a tender skin. 

 The Eutrichid larvae are generally solitary, but those of Dendrolimus 

 howardi are stated (Journ. N. Y. Ent. Soc., 1896, p. 23) to be 

 gregarious, forming a web or tent, and Tourney says that great 

 bands of web hang from the branches immediately around the 

 tent, like long streamers. 



It may be here noted that Suckow's investigations into the 

 development of the female generative organs and the accessory 

 structures were carried out on larvae of Dendrolimus pini. He 

 found the two filamentous oviducts to be prolonged beyond 

 their point of attachment between the 7th and 8th abdominal 

 somites, as two separate broader and longitudinally striated bands 

 which end in contact with two small white knobs. They shorten 

 gradually in the quiescent caterpillar and are thickened at the 

 commencement of pupal life, and, by their union, they form the 

 vagina. The two knobs just mentioned are, at the outset, separated 

 from one another by a slight space, and are fixed to the hypodermis, 

 whilst a nerve derived from the terminal ganglion of the chain 

 passes to each of them. During the time that the formation of the 

 vagina is taking place, the knobs approach each other and unite; 

 moreover, they are brought by the contraction of the muscles and skin 

 in pupation into opposition with the attached ends of the two oviducts. 

 They are destined to give rise to four swellings' — the rudiments of 

 the bursa, the receptaculum and the two sebaceous glands. These 

 conclusions are criticised by Jackson {Studies Morph. Lep., pp. 

 155 and 170). 



There are two very distinct forms of cocoon made by the 

 Eutrichid larvae known to us, viz., the smooth parchment-like 

 form exhibited by that of Cosmotriche potatoria, and the more loosely- 

 woven form, largely intermixed with hairs, seen in its extreme form, 

 perhaps, in the cocoon of Eutricha quercifolia. The cocoon of 

 Macrothylacia rubi is probably to be referred to the latter group. 

 Dyar's description of the cocoon of Dendrolimus howardi ( Journal 

 New York Ent. Soc, iv., p. 26) suggests a rather near relationship to 

 Cosmotriche. He describes it as " thin, almost papery, of dark-brown 

 silk, single, but with some loose silk without, elliptical, less definite 

 in shape than in Clisiocampa, the ends thinner than the central portion." 



Standfuss records having experimented on eggs of Odoncstis pruni 

 and Dendrolimus pini, which he exposed to a temperature of 34°C. 

 (93°F.) during the process of laying by the females and afterwards kept 

 at this temperature until the time of hatching. As a result they produced 



