creatures, the ant-eating mammals, who dig open their strongholds and devour 

 them by the thousand at a meal. 



The Neuroptera (for convenience I follow the old arrangement and include 

 the dragon-flies in this order) have, in the matters of outward form and dis- 

 guising-coloration, much in common with the aerial insects already considered, 

 but also a few salient points of difference. As everybody knows, the typical 

 dragon-flies (Libellulidce) sit with their four large gauzy wings fully outspread 

 in a single plane. Too finely-netted to be perfectly transparent, these wings 

 (in addition to being iridescent) are very often marked with bold obliterative 

 bands or spots of opaque color, like that of sticks and bark and shadows — 

 brown, brown-red, dusky — and these markings go far toward making the 

 wings invisible against their average backgrounds.* The long and slender, 

 stick-like body also is often marked with obliterative cross-bars, and oblitera- 

 tively shaded. For the true dragon-flies, unlike most of the insects we have 

 been considering, habitually perch back-uppermost, — or sometimes vertically, 

 but rarely or jiever upside down. Hence in their disguisement there is op- 

 portunity for counter shading and picture-patterns to come fully into play. 

 The patterns they wear are of many kinds and many colors (green, red, yeUow, 

 blue, and black perhaps predominating), but almost all are transverse and 

 most of them are very simple. Their counter shading of course takes in not 

 only the attenuate abdomen but the thorax and big head; in short, the whole 

 main form of the insect. The proportionately enormous compound eyes 

 are usually rather dim-colored, but more or less iridescent, and very inconspic- 

 uous. Gorgeous iridescent foliage-color — cold blue to golden green and 

 yellow — is common in the costumes of dragon-flies, and highly characteristic 

 of some groups. As they are bird-like in their light, upright perching and 

 sudden, swift, aerial sallies in pursuit of their flying prey (from which dashes 

 they often return to the same perch), so are they bird-like — ^though also like 

 butterflies and lizards — in the splendor of their obliterative, vegetation-picturing 



* Their concealing-coloration probably serves them even more vitally in their aerial hunting 

 than as a protection. — A. H. T. 



208 



