IMAGO OF PRIVET HAWK MOTH. 157 



of black hairs to its posterior margin. This black fringe encroaches more 

 and more on the surface of the somites at the expense of the pink band 

 the further back the somite is in the series. 



The female differs from the male as follows. The antennae are more 

 slender, and want the setae-like hairs on the brown surfaces of the joints : 

 the thorax is rounder in front and the fore-wings have generally a more 

 curved anterior border and less acute apex : there is no hook developed on 

 the fore-wings for the bristle. There are five pink bands on the abdomen 

 instead of six : the last somite is broad basally, conical and as long at 

 least as the two preceding somites, whereas in the male the abdomen 

 tapers gradually to a point and is terminated by two valves with a vertical 

 slit between them. 



The Lepidoptera are often divided into two chief sub-groups the Rhopa- 

 locera with the antennae ending in a club, and the Heterocera to which 

 Sphinx belongs. The Heterocera have various types of antennal structure. 

 They frequently possess the retinacular apparatus binding the fore- and 

 hind-wings together, and their posterior tibiae have four instead of two spines. 



The Sphingidae, the family of which Sphinx is the type, are characterised by 

 the prismatic shape of the antennae and the long bristle-like character of their 

 terminal joint ; by a three-jointed very hairy labial palp with a minute terminal and 

 two broad compressed basal joints ; by a one-jointed maxillary palp ; a robust body 

 and relatively small wings. Their mode of flight is peculiar and sustained. Hence 

 the popular name of Hawk-moths given to these insects. Ocelli are generally 

 stated to be absent, but Cattie affirms their existence in Acherontia Atropos. 



To see the form and composition of the regions of the body it is necessary to 

 divest it of hairs and scales by careful brushing. The head has no sutures. The 

 prothorax is ring-like and is hence often termed ' collar.' Its tergum carries at each 

 outer angle a vesicular dilatation clothed with long hairs, the patagium of Kirby and 

 Spence. The prothorax is united to the mesothorax by membrane, but the latter 

 and the metathorax are firmly connected. The mesothorax is very large. Its 

 tergum is broken up into a large scutum and a lozenge-shaped scutellum behind. 

 The fore-wings are attached to it, but their roots are covered by concavo-convex 

 shields, the tegulae or wing-covers 1 . The metathorax is small. Its scutum is 

 narrowed medianly where the scutellum projects forward. It bears the hind wings. 

 The nervures of these organs become plain when the scales are brushed off. They 

 contain extensions of the tracheae and blood-channels. For their arrangement, as 

 well as the composition of the lateral walls of the thorax, the student must consult 

 the larger works on Entomology. The limbs consist of the same parts as in the 

 Cockroach. The anterior coxae are free ; the median and posterior are closely 

 attached to the thorax. The trochanter is small ; the femur short. The anterior 

 tibiae have at their proximal end a peculiar enlarged moveable spine. The median 



1 The terms ' patagium ' and ' tegula ' are often misapplied. They are defined as in the 

 text above by Kirby and Spence in the Orismology, Vol. iii. of the Introduction to Entomology. 

 Patagia are structures peculiar to Lepidoptera, whereas tegulae are found in various other orders. 



