124 HYMENOPTEEA. 



flower, producing a sharp and intermittent buzzing, and many of 

 the species exhale an odour of roses. 



Family XIV. — Pompilidce. 



Collar either transversely or longitudinally square; legs long; 

 abdomen oval, and attached to the thorax by a short petiole. 



A very extensive group, having representatives in all parts of 

 the world ; the species are black, sometimes with red legs and 

 antennae, and the abdomen is often red, especially at the base ; the 

 wings may be colourless, banded with brown, or marked Avith 

 whitish ; or yellow, or brilliantly iridescent blue. Many of the 

 European species provision their nests with spiders, while others 

 store up caterpillars, etc. Some of the species of the tropical 

 genera Pepsis, Fabr., and Mygnimia, Smith, are among the largest 

 of Hymenopterous insects, measuring three inches or more across 

 the wings. 



Family XV. — Sphegldce. 



Prothorax narrowed in front, and the hinder angles not pro- 

 duced to the base of the wings ; abdomen with a long round 

 petiole, consisting of the first and sometimes part of the second 

 segment ; wings rather short. 



The shape of the Sphcgidce will at once distinguish them from 

 almost all other Hymenoptera, except some of the Vespidce ; but the 

 latter have the sides of the prothoi^ax prolonged backwards to the 

 base of the wings. Certain Ichneumons also resemble them in 

 shape ; but, apart from other characters, the nervures of the 

 wings are very differently arranged in these from what they are 

 in any Aculeata. Different species of Sphegidce provision their 

 nests with different insects, or with spiders. They sometimes 

 attack insects much larger and stronger, or apparently better de- 

 fended than themselves, such as field-crickets, weevils, etc. ; but 

 they paralyse them by striking their sting into the principal 

 nervous centres, and then drag them to their nests, where they 

 bury then alive, but paralysed, so that a living but helpless prey 

 is provided for the larvae when they shall emerge from the eggs. 



Some of the tropical Sphegidce, belonging to the genera 

 Chlorion, Latr., and Ampulex, Jur., are of a beautiful metallic 

 blue or green ; Ampulex Compressio, Jur., which is found at Mauri- 

 tius, etc., preys on Blatiidce. Froneus Mazillarls, Latr., a common 

 black West African species, is remarkable for the enormous 

 mandibles of the male. 



