768 CLASS IV. INSECTA. 



of various Aculeate Hymenoptera, Mutilla europaea in the nests of 

 Bombus. Three species are British but rare. 



Sub-fam. 2. Thynninae. Males winged, females wingless ; in the 

 latter the thorax is divided into three sub-equal parts ; no constric- 

 tion between the second and third abdominal segments ; wing ner- 

 vures reach the edge of wing. This sub-family is also ant-like, the 

 single and rare British species Methoca ichneumonides being often 

 taken for an ant. Their most striking feature is the extreme difference 

 between the two sexes. 



Sub-fam. 3. Scoliinae. One apical spur on second tibiae ; both 

 sexes winged ; wing nervures do not reach edge of wing ; legs stout. 

 This sub-family includes many large and hairy forms, the females 

 usually larger than the males. They generally lay their eggs in such 

 larvae of Lamellicorn beetles as burrow in the ground, e.g. Scolia 

 bifasciata in the larvae of Cetonia. The group is largely tropical. 



Sub-fam. 4. Sapyginae. Slender legs and antennae, abdomen 

 not ending in spines. The single genus Sapyga lays its eggs in 

 bees' nests, e.g. those of Osmia, and its larva devours the food laid 

 up for the young. Two species occur in Britain. 



Sub-fam. 5. Rhopalosominae. Antennae long and spiny ; ocelli 

 very large ; tarsi peculiar, claws bifid. A single genus Rhopalosoma 

 of unknown habits. 



Fam. 21. Pompilidae. Pronotum reaches base of wing ; no constric- 

 tion between second and third abdominal segments ; posterior legs long ; 

 eyes elliptical and not crescentiform. A very large family of wasps which 

 dig nests in banks, etc., and store them with the paralysed bodies of spiders 

 or more rarely of insects. In this way Pompilus and Calicurgus destroy 

 large numbers of spiders, usually of the more voracious kinds. These 

 wasps are active walkers and generally drag their victims to their lair along 

 the ground. It is characteristic of many Pompilidae to run swiftly along 

 the ground, with quivering wings and vibrating antennae. Some species 

 are very large. Pepsis frequently attains a length of two inches and 

 can overcome spiders as big as the Tarantula. The family is widely 

 distributed. 



Fam. 22. Sphegidae. Pronotum short and not reaching to base of 

 wings ; when the stigmatic lobes reach to the level of the insertion of the 

 wings, they are below and separated from the place of insertion. This very 

 large family is probably not a natural assemblage ; it is divided into ten 

 sub-families : 



Sub-fam. 1. Spheginae. Abdomen with a slender pedicel ; two spurs 

 on the second tibiae. A large group with Sphex as the chief genus. It 

 burrows in the ground and stores its cells with the paralysed bodies 

 of crickets, grass-hoppers and locusts. Ammophila uses caterpillars 

 for the same purpose. Pelopaeus usually makes its home in human 

 dwellings and stores its larder with spiders. 



Sub-fam. 2. Ampulicinae. Prothorax elongate, produced into a 

 neck in front ; clypeus beak-like ; four submarginal cells ; metathorax 

 long and ventrally split to permit of the forward flexure of the ab- 

 domen. A widely distributed sub-family with few species and few 

 individuals. They feed on cockroaches. Ampulex forms no nests. 

 Sub-fam. 3. Larrinae. Xo pedicel or at most a very short one, 

 the second tibiae have but one spur ; marginal cell of fore-wing 

 appendiculate, i.e. with a second cell more or less completely marked 



