242 The Orders of Insects 



scales are characteristic of this family which, very widely spread 

 over the old world tropics, is represented in Europe by two species 

 only ; neither of these is certainly known to inhabit the British 

 Islands. 



Thyatiridae. — The Thyatirida are a small family of moths which 

 differ from the families hitherto considered in the second median 

 nervure of the forewing coming off from the cell midway between 

 the first and third, the other nervures not being, as in the Sesiidse, 

 Tineids, etc., evenly spaced around the cell. In the hindwing the 

 sub-costal nervure bends towards and nearly touches the radial 

 beyond the cell. The frenulum and first maxills are well-developed ; 

 the feelers are thread-like. In the appearance of the moths and in 

 the form of the larvse this family is suggestive of the Noctuids. It 

 is fairly represented throughout the northern regions but becomes 

 reduced in numbers in the tropics. 



Notodontidae. — The Notodontida are a family of fairly large moths 

 nearly allied to the Thyatirids, but the sub-costal nervure in the 

 hindwing diverges from the radial (wherewith it is sometimes 

 connected by a cross nervule) after the middle region of the cell. 

 The threadlike feelers are sometimes pectinate in the male. The 

 larvs are usually without pro-legs on the hindmost segment, which 

 is carried erect, and other of the segments often bear hump-like 

 processes. (Hence the name of "Prominents" given to members 

 of this family.) The pups are naked and buried underground. The 

 moths are stout in build with hairy feet ; the tarsal segments 

 together not longer than the shins ; they are found throughout the 

 world except in New Zealand. 



Sphingidae. — The Sphingida or Hawk-moths are a large family of 

 big, stoutly built moths, closely allied to the Notodontidx but 

 distinguished by their thick spindle-shaped feelers, which end 

 generally in a hooked tip. The first maxills are very long, and the 

 insects suck honey while on the wing, their flight being very power- 

 ful. The forewings are long and pointed, always much longer 

 than the hindwings, in which the sub-costal nervure is free through- 

 out its length from the radial and connected therewith with a 

 cross-nervule. The caterpillars, always with ten pro-legs, are 

 destitute of hairs, but a prominent spine or process is usually 

 present on the back of the hindmost segment. The subterranean 

 pupa is not enclosed in a cocoon (fig. 134). The family is world-wide 

 in its range. 



Dioptidae. — The Dwptida are a small family of day-flying moths 

 with slender bodies, and feelers which are comb-like in the males. 

 The sub-costal nervure of the hindwing is unconnected with the 

 radial ; otherwise the neuration is similar to that of the Notodontidse. 

 The wings of the Dioptidje are largely destitute of scales, and the 

 moths bear an outward resemblance to certain butterflies of the sub- 

 family Ithomiinz. They occur only in tropical America. 



Geometridae. — ^The Geometrlda are a very large family of moths 



