ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 141 



is of no direct use to the ants. There are two protrusible papilla?, 

 with a terminal wreath of very fine hairs. When the caterpillar is 

 touched by an ant the papilla? are protruded, and a scent attractive to 

 ants is exhaled. The caterpillar is always attended by ants, who afford 

 it protection. Ehrhardt finds that when the ant is touched by 

 small centipedes or beetles, or the like, the scent-organs are protruded. 

 But there was no secretion except when he held the centipede so that 

 it touched only the area of the secreting organs with its antennas and 

 first pair of legs. By means of other stimuli, thermal and electrical, 

 the protrusion of the papillae and an activity of the secreting organs 

 can be induced. Ehrhardt was able by using an electric current to get 

 ten secretions in lj minutes. 



The secreting organ in the full-grown caterpillar consists of four 

 secretory vesicles, which project far into the body-cavity and fill up the 

 greater part of segments 1), 10, and 11 ; each consists of two giant cells, 

 a pear-shaped one in contact with the slit, and a large irregular one 

 beneath it, and acting as a reservoir. The external part of the pear- 

 shaped cell is really closed, but the membrane is very delicate and pro- 

 trusible. These remarkable cells probably correspond to the couple of 

 cells found at the base of each of the hollow glandular hairs which 

 are frequent on the skin. The lower one sends a plasmic strand 

 through the upper one, and this strand secretes the chitinous hair. 



The secretory organs of Lycsena orion do not appear until after the 

 first moulting, and there are at first two. The development indicates 

 that they are transformed glandular hairs, and the process is described. 

 During the second moult the first two secretory vesicles are absorbed 

 and two new ones are formed. In the next moult these are absorbed and 

 four new ones are formed. The opening of the slit and the exudation 

 of the secretion are due to blood pressure. 



The scent-organs are not developed until after the second ecdysis. 

 They are evaginations of the hypodermis. At the end of the evaginated 

 papilla there is a circle of wart-like elevations, each with a very thin 

 hollow seta, which, again, bears a spine-like process. Thus a large 

 surface is formed for the exhalation of the scent. Each hair has a 

 unicellular gland at its base with a very large nucleus, rich in chromatin. 

 The protrusion is due to blood pressure ; the retraction is brought 

 about by a muscle attached to the apex of the papilla. The two kinds 

 of organs disappear in the pupa state, and there is no trace of them in 

 the adult. 



Variations in Italian Lepidoptera.* — Roger Verity gives an account 

 of a number of variations observed in Lepidoptera collected in Tuscany 

 and other parts of Italy by 0. Querci and himself. He deals with 

 species of Parnassius, Melitsea, Aryynnis, Melanargia, Erebia, Epin&phile, 

 Ccenonympha, Thecla, Chrysopkanus, Lycsena. and Syntomis. 



Nocturnal Observations on Ants.f — V. Cornetz relates some inter- 

 esting observations on the way-finding of ants. Thus, in regard to a 



* Bull. Soc. Entomol. Ital, xlv. (1914) pp. 203-38 (1 pi.), 

 t Rev. Suisse Zool., xxii. (1914) pp. 581-95. 



