NOTES ON THE LIFE-HISTORY OF AGLIA TAU. 237 



lie in wait for them, proceed to the task of founding new colonies. 

 Ants and white ants have much that is analogous in their modes of 

 life. They belong, however, to two widely-different orders of insects, 

 strongly contrasted in their structure and manner of growth." 



Notes on the life=history of Aglia tau. 



By ARTHUR W. BACOT, F.E.S. 



Ovum (April 25th, 1900). — The ovum varies greatly in length and 

 colour, from pale Avhitish-yellow to dark red-brown. Shape, a blunt- 

 ended oval, almost circular in cross-section, i.e., a cylinder with 

 rounded ends. There is great disparity in size, and occasionally the eggs 

 are bent and flattened on sides (oval section), giving them much the 

 appearance of a French bean. The sizes of three measured work out 

 as follows : — 



Length. Breadth. Thickness. 



•llinp. -OGins. -Oooins. 



•075ms. •0675ins. -OSins. 



•115ins. -OGins. -OGins. 



The last of these was straight, surface much wrinkled, and pale 

 orange in colour. The surface is minutely pitted, and has traces of a 

 fairly large, but very faint, cell reticulation. Scattered either singly 

 or in little detached groups, much as the] Smerinthid eggs are in 

 captivity. 



Habits of young larv.e. — The larvte live solitarily, rest on the 

 underside of a leaf in the " Sphinx " position, and move little, though 

 occasionally they may be seen crawling along the twigs of leaf-stalks. 

 Their habits agree closely with those of young larva; of Mimas tiliae or 

 SpJiinx li(/tistri. 



Description of young larva (May 15th, 1901). — 1st skin (well- 

 grown in 1st stadium) about twice length of newly-hatched larva. 

 The habits are almost the same as those of a young Sphingid larva, 

 ('.//., Ji. tiliae or S. liijustri, resting on underside of leaf, sluggish, and 

 moving little, adopting the "Sphinx" attitude when not actually 

 feeding. In feeding it only exposes its head, working in the gap it eats, 

 its body concealed, looked at from above, by the leaf. The larvas 

 already show traces of the habit of withdrawing head beneath the 

 prothorax. Head rounded, but with a tendency to flattening at top 

 and sides ; slightly depressed or notched at crown ; colour pale 

 creamy white, with a broad band of pale red-brown over crown and 

 down sides ; the clypeal suture also bordered Ijy a broad band of 

 same colour ; surface smooth, but not shiny, and under microscope (1" 

 objective) is seen to be spotted with dark on pale ground ; hairs 

 scattered, pale and transparent, looking finely thorned or serrated. 

 7jo(/// cylindrical, plump, and stout for length, with deeply-cut 

 segmental divisions ; the larva tapers forward from metathorax to 

 head, and backwards from 1st alodominal to anus, the 7th and 8th 

 abdominals being noticeably smaller than the other abdominal seg- 

 ments, 9 and 10 are also rather more dwarfed than usual ; colour 

 bright apple-green, rather paler and duller on the ventral area, with a 

 raised and paler-coloured prominent lateral flange ; prolegs almost 

 colourless, but brown at foot, legs also pale and semitransparent 



