the Biology of some British Neuroptera. 587 



what smaller. The vicinity of the middle line is white. The two 

 black, diamond marks are in contact and so leave laterally, in pro- 

 and mesothorax, also in fore and hind abdomen, white patches. 

 The remaining few small hind segments of the abdomen are whitish, 

 with central blackish markings. The last two segments are colour- 

 less and transparent. There is a median longitudinal dark crimson 

 line, starting about the mesothorax and running almost to the tip 

 of the abdomen. The underside of the body is greyish-white marked 

 with black, and where the dorsal markings reach well down the 

 sides they generally continue partly across the venter. Legs greyish, 

 translucent. 



All black markings mentioned above are due to hypo- 

 dermal blue-black pigment, which appears as such in the 

 early part of each instar, but later in the instar tends to 

 become dark brown. 



For pupation a small flat cocoon of white sMk is spun, 

 on a twig or in a crevice. The cocoon does not show the 

 double structure as well as does that of Conivenizia, and is 

 not truly double. The la,rva first spins above and below 

 itself a silken covering of 3-4 mm. diameter. Then a ring 

 of silk, 2 mm. diameter, is spun connecting together the 

 upper and lower silk surfaces. The change to pupa takes 

 place in about four days, and a week later the imago 

 appears, after biting a semicircular slit in the silken envelope 

 with its pupal mandibles. In the case of larvae from the 

 second brood, the winter is passed as a larva within the 

 cocoon and pupation occurs in spring. 



The two examples in the table have been selected, as 

 they give a variation in life-cycle of two specimens from 

 eggs laid almost simultaneously. The backward season 

 and cold weather probably account for the second case of 

 a first-brood larva hibernating. 



The food of Semidalis, larvae and adults on oak, appears 

 to be often Phylloxera punctata Licht., and this is the 

 easiest food on which to breed them in captivity as they 

 do not take kindly to aphids, as a rule. Also on oak they 



