MIMAS TILI.dE. 401 



Sexual dimorphism. — In a series of specimens, the $ s and 

 2 s have a somewhat different facies, due chiefly to the greater 

 robustness of the body of the 2 , which is perhaps more marked 

 in this species and Amorpha populi than in most other Sphinges, 

 affecting the thorax as well as abdomen. In the $ the wings 

 are also shorter and narrower basally, and wider at the hmd 

 margin than in the £ . In A. populi, the notches between the 

 nervures of the forewing are nearly equal, except that nervure 5 is 

 short and the notch here is from 4 to 6. In M. tiliae the notch is 

 enlarged into a deep sinuation by 4 retreating as well as 5. This 

 condition is more pronounced in the $ than in the $ . The $ 

 coloration is darker than in the 2 , but the range of variation in 

 races and specimens is so great that individual series may show 

 the females the darker. The antennae differ as in all other 

 Sphinges, in the g s having the usual cups of cilia well marked, 

 while the 2 shows only a small median lateral bristle at margin 

 of scaled area. The $ antenna has about 54 joints, that of the 

 ? about 52, but there is some variation. In the $ the anterior 

 tibial spur reaches nearly to the end of tibia ; in the ? it falls 

 decidedly short of this point ; the posterior tibial spurs are larger 

 in the $ than in the 2 (Chapman). 



Gynandromorphism. — Very few gynandromorphous specimens 

 of this species have been recorded. The following are the only ones 

 we trace : 



a. Left ? , right <? . Coloration on the right side olive-green with dark 

 median band ; lighter on the left side, and more yellow-green, with median 

 band correspondingly lighter. The patagia and underside of the wings correspond 

 with this coloration. Right antenna S , left ? . Abdomen <J . Captured near 

 Berlin. Coll. Wiskott, Breslau (Wiskott, Festschr. Schles. Ver. Ins., p. 109). 



(3. Referred to by Schultz as described in Russ's Isis, iv., 1879, no - 2 ° (Woch. 

 fur Ent., i., p. 367). We have quite failed in our attempts to get the description. 

 y. A gynandromorphous example in coll. Staudinger (in litt.j (Schultz, Woch. 

 fur Ent., ii., p. 393 ). 



Variation. — The species is very variable, both in colour and 

 in the amount of development of the median transverse band; 

 rarely are two specimens exactly alike, and they are very frequently 

 asymmetrical, the colour and markings of the left wings differing from 

 those of the right. Clark's plate (Ent. Rec, i., pi. A) exhibits 

 this peculiarity well. Turner notes (Proc. Sth. Loud. Ent. Soc, 1894, 

 p. 50) an asymmetrical specimen taken at Greenwich, in which the 

 right side is of a deep green and rich ferruginous-brown, whilst the 

 left side is of a much paler green and brown, the latter being smoky 

 in places ; also the lower of the two blotches on the left forewing 

 is very narrow, the corresponding one on the right forewing being 

 very large. Bartel notes rare aberrations of a very bright 

 yellow colour ( = ab. lutescens, n. ab.), and says that the progeny of such 

 individuals as have been inbred for many years in captivity are 

 usually much more distinctly and prominently marked than the 

 normal imagines taken wild, and are distinguished also by the hind- 

 wings being exceptionally heavily-marked with black ( = ab. suffusa, 

 Clark). Very dark greyish-green individuals with almost com- 

 pletely black hindwings are recorded by Caradja as being 

 found in the Department of the Haute-Garonne in October, and 

 bred from larvae collected at me commencement of the same 



2 B 



