228 ENTOMOLOGY FOR MEDICAL OFFICERS 



comb and take charge of the larvae afterwards produced from 

 the queen's eggs. In late summer males and perfect females 

 are produced : in autumn the community dies off, except for 

 such females as may succeed in hibernating. Wasps' nests 

 are constructed of a sort of paper made of mashed vegetable- 

 tissue ; the combs are generally placed in tiers. Even in 

 hot countries like India, the wasp communities die off at 

 the approach of the cooler season. 



(c) Fossores (Lat fossor = a digger, or miner). The 

 fossorial wasps are never social, and rarely gregarious. 

 Some of them — chiefly certain forms in which the female is 

 wingless and ant-like — are "parasitic" in the same way as 

 Ichneumon-flies, etc. {i.e., the female victimises the larva of 

 some insect as a living receptacle for her eggs and a living 

 pabulum for the ensuing larvae); but with most of them 

 the female lays her eggs either in burrows or in specially 

 constructed cells of mud, depositing in each cell, along with 

 an egg, a provision of insects or spiders for the sustenance of 

 the future larva, and then sealing up the cell, and, as a rule, 

 leaving it to fate. The insects so used as provision are, 

 usually, not killed but are paralysed or narcotised by a sting 

 delivered in some non-vital part ; and as a rule each species 

 of wasp prefers a particular kind of insect for its purpose. A 

 few Fossores have a slight resemblance to bees, but can be 

 distinguished by the unmodified hind legs and by the absence 

 of feathered hairs ; some, with wingless females, resemble 

 ants, but can be distinguished by the absence of nodes on the 

 stalk or petiole of the abdomen ; but the great majority look 

 like wasps, from which they can be distinguished by the 

 absence of the longitudinal fold of the front wing. The 

 following families may be noticed: — Pompilida — large 

 fossorial wasps, sometimes 2 or 3 inches long, and probably 

 able to inflict a grievous sting ; the pronotum is of good size 

 and the hind legs are very long : they run rapidly, quivering 

 with energy, and they store their cells with paralysed spiders. 

 Sphegidce~t\\e. pronotum is short, often a mere collar, in this 

 very large family ; the different species store their cells with 

 insects of all sorts as well as spiders, each species according 

 to its wont. The genus Bembex, in this family, requires 

 particular notice, as its prey consists of Diptera, and it has 



