FAMILY HABITS IN BUTTEKFLY LARVJE THE PAPILIONIDS. 25 



in the same direction, whilst (p. 1525) the larva of Pholisora Catullus 

 lies with its anterior segments bent round, so that the head comes 

 a little beyond the middle of the body, and, in nearly every instance, 

 the tail towards the closed end of the tent. It may be noticed that the 

 curving of the body in this manner leads to the larva occupying the 

 least possible space in a horizontal tent, and allows the latter to 

 be made of small size compared with the size of the larva. This is, 

 of course, largely a Hesperiine habit, the Urbicolines making a 

 longitudinal nest and resting in it at full length, usually folding 

 a leaf in the direction of the veins, the cylinder often only just 

 wide enough to hold the larval body. The exceptional habit 

 of the larva of Halpe moorei, when about to pupate, as noted by 

 Davidson, Bell, and Aitken, should, perhaps, not be passed over ; it is 

 said to form a special tent by folding over a bamboo leaf in its last 

 instar, and then, when fullfecl, to eat the leaf free at the stalk-end, 

 so that its- celi falls to the ground, where pupation takes place. An 

 almost similar habit has been noticed in the larva of Padrcwna dara 

 which also feeds on bamboo and eats the leaf almost through at the 

 base of its tent, so that it often finally falls to the ground, the larva 

 pupating in the fallen shelter. 



It will be seen from this short chapter that our knowledge of the 

 larval habits of the Urbicolids is very imperfect and scrappy, quite 

 insufficient and too general to be of real use in drawing conclusions of 

 family habit in many directions, although sufficiently so to give us 

 excellent clues as to these habits in other directions. We can only 

 urge that the poverty of facts has not been due to want of energy in 

 attempting to discover such, but that it is largely owing to the imper- 

 fection of the records made by those who, in various countries, have 

 not given us all the details that must have resulted from their 

 observations. 



CHAPTER III. 



FAMILY HABITS IN BUTTEEFLY LARY.E THE PAPILIONIDS. 



In their widest sense, the Papilionids are generally held to contain three 

 main divisions, the Papilionmes, the Thaines and the Parnassiines. Only 

 one of these, the first-named, has a British representative, and that but 

 a single species, viz., Papilio machaon. The larvse of all these groups, 

 however, have certain characters in common, one of the most remark- 

 able of which, as bearing on the habits of the larvte in the widest 

 sense of the term, may be mentioned here. This is the osmaterium, 

 a peculiar, retractile, forked or Y-shaped organ, generally stated to be 

 a scent-gland, placed on the dorsum of the prothoracic segment. This 

 is usually brightly-coloured, wholly concealed when the larva is in a 

 state of rest, but can be suddenly protruded if the larva be disturbed or 

 alarmed. We have already fully described its structure {A Nat. Hist. 

 Brit. Lep., vol. i., p. 95 ; vol. viii., pp. 22-23). 



The structure must be well-known to all British lepidopterists, as it 

 appears in the larva of Papilio machaon, but Wallace says (Xat. Selec- 



