224 BRITISH LEPIDOPTERA. 



of the front part of the flange on each segment into an oblique red stripe 

 extending across the ist, 2nd and 3rd subsegments of each abdominal, 

 and by being almost continuous on the thoracic segments ; each of 

 these stripes bears, on the abdominal segments, a yellow patch directly 

 below the spiracle, and this carries a stumpy hair, the specialised 

 appearance of which leads one to homologise it with a subspiracular 

 tubercle (iv). The area between the flange and venter is of the 

 same black colour as the dorsum, and with similar yellow spots ; and 

 this characteristic mode of marking is carried almost entirely-round the 

 venter of abdominal segments 1 and 2. The remainder of the venter 

 is reddish with a dark blackish-grey patch medially on each abdominal 

 segment (either between, or in the position of being between, the prolegs). 

 The prolegs are short and thick, reddish in colour, rather hollow cen- 

 trally, with the outer edge forming a strong flange not very plentifully 

 supplied with red-brown hooks ; these are in pairs, alternately long 

 and short, and 33 in number ; the anal prolegs are fixed angularly 

 against each other, and are, like the other prolegs, sparingly sprinkled 

 with short blackish hairs. The true legs are also of a reddish 

 colour, each with one strong black curved hook, the joints fringed 

 with short blackish hairs (Tutt. Described from larvae from La 

 Grave, August 16th, 1896). We may here note that in Hyles euphorbiae 

 the ovaries in the ? larva are yellow, the testes of the $ larva 

 reddish (Bessels), whilst in the larva oi Sphinx ligustri both 

 ovaries and testes are white *. 



Variation of larva. — We have already described certain 

 forms of this exceedingly variable larva. At the commencement 

 of the fifth instar, a large number of larvae, obtained at Evolena 

 in August, fell into three forms (anted, p. 221). As they neared 

 maturity much more individual variation was noticeable, and one 

 could safely say that when quite fullfed scarcely any two larvae were 

 alike. The commonest form appeared to be that in which the 

 head, mediodorsal line, caudal horn, lateral flange, anal segment, 

 anal prolegs, prolegs and true legs were yellow; the anterior wide 

 (ist + 2nd) subsegment black, carrying the two yellow lateral spots 

 on either side ; the six narrow subsegments spotted, but with a 

 yellowish lateral blotch on each side, extending the width of the 

 last five subsegments. A somewhat rare form has this lateral 

 series of yellow or orange-yellow blotches obliterated (or almost 

 so) by the spotting being continued all over the segments. Others 

 again have the black of the ist + 2nd subsegment continued back on 

 the succeeding subsegments with only a few pale dots on the last three 

 subsegments of each segment. One or two have, on the other hand, 

 the black of the ist + 2nd subsegment spotted so much laterally as 

 to almost lose the usual annular, or black-banded, appearance. There 

 is, in all these, great difference in the intensity of the tint of the 

 yellow parts, some of the larvae having quite a deep orange medio- 

 dorsal line, lateral flange, prolegs, etc. The red form, already 

 described (anted, p. 222), appears to me one of the most handsome. A 

 few of these Evolena larvae that Chapman brought to England were 



* For the sake of those biologists who require the information, it may be well 

 to note that Rengger, in his Pkysiologiscke Untersuchungen titer die thierische 

 Haushaltung der Insecten (18 17), has made considerable use oi Hyles euphorbiae for 

 his anatomical investigations. 



