THE HUTILLID^E. 



377 



and females differ greatly from each other in many respects, the latter being often destitute of wings, 

 or having those organs greatly reduced in size, whence the name Heterogyna has been given to the 

 group by many entomologists. In both sexes, however, the legs are comparatively short and hairy, or 

 spinose, but with long tarsi ; the eyes are notched on the inner margin ; and between the first and 

 second segments of the abdomen there is a notch or constriction. The group includes a large number 

 of species probably 1,200 or 1,300 but from the differences presented by the males and females 

 entomologists have found it difficult to arrive at any certainty upon this point. The species are spread 

 over all the earth, but are particularly abundant in warm climates, where also, as usual, they attain 

 the largest size and the most beautiful colouring. 



In the genus Mutilla, from which the family name is derived, and in the allied genera, which 

 include the great bulk of the species, the peculiarities of the group are most strongly marked, and the 

 differences between the sexes so striking that until comparatively recent times the males and females, 

 even of well-known species, were referred to distinct genera, and sometimes rather widely separated. Of 

 Mantilla some 500 species are known from all parts of the world, and three of them occur in Great 

 Britain. They are found usually in sandy spots. In this genus the females have no ocelli. The 

 most abundant European and British species (Mutilla europcea) is about half an inch long, of a black 

 colour, hairy, with the thorax entirely red in the wingless females, red in the middle in the winged 

 males ; the abdomen has three transverse bands of white or yellowish hairs, the two hinder of which 

 are interrupted in the middle. The wings of the male are brownish. The females of this and other 

 species have an aspect intermediate between that of a Spider and that of an Ant, whence the German 

 entomologists give them the very characteristic name of "Spider Ants." The habits of the species are 

 not very well known. The Mutilla europcea frequents the nests of Humble Bees, and its larvae appear 

 to be parasitic upon the larvae of the Bees. Mr. Drewsen of Copenhagen obtained only two Worker 

 Bees from a nest of JBombus skrimshiranus taken by him, which furnished seventy-six examples of 

 Mutilla europcea, forty- 

 four males and thirty- 

 two females. The larvae 

 of the Mutilla were 

 found in the cocoons 

 which had been formed 

 by the full-grown larvae 

 of the Bee. The females, 

 after impregnation, pass 

 the winter rolled up in 

 the ground or under 

 stones. Both sexes of 

 this and other species 

 can produce a faint 

 chirruping sound by the 

 friction of the third and 

 fourth abdominal seg- 

 ments upon one another ; 

 and the special arrange- 

 ments for producing this 

 noise consist of a small 

 triangular finely -ribbed 

 area upon the upper 



surface of the fourth segment, over which passes the hinder margin of the third segment, furnished 

 beneath with a little sharp ridge. These parts are rubbed together by the extension and retraction 

 of the fourth segment, which slides in and out of the third like the draw-tube of a telescope. 



A great number of species of Mutilla occur in South America, which is also the home of another 

 important genus (Thynnus), likewise largely represented in Australia. 



In another group of the family, formed by the genus Scolia and its allies, the female is winged, 

 238 



MUTILLA EUROPCEA. 



