April, 1918] Parasites oj Leaf -Hoppers 193 



Mimicry. — Along with the loss of wings in the female, there 

 has been developed the remarkable resemblance to ants in 

 many forms. This has been adaptive and due entirely to 

 the mode of life of the female. Not only have the wings been 

 lost, but the legs have been modified for running, and the 

 forelegs especially for grasping the prey. Thus the thorax has 

 become greatly modified and more closely fused with the 

 propodeum. In the more highly specialized species, many of the 

 thoracic sutures have been obliterated and segmentation of 

 the thorax is indistinct. The latter is divided into two nodes 

 by the narrow mesonotum, and may even be divided into three 

 nodes. This division of the thorax and the pedunculate form of 

 the first abdominal segment are adaptations to the stinging 

 habit of the female, enabling her to bend the entire body in an 

 arc while stinging the prey. 



Many species have evidently taken advantage of this ant- 

 like form and are frequently found associated with ants, some- 

 times being found in the nests of the latter. This association 

 in the case of Platygonatop^is pedestris (Dalm.) was observed 

 by Haliday in 1834, when he says: "The first time I met with 

 this species, it was in company with some Myrmicce (not M. 

 rubra), under a stone, in a chalky lane. * * * In this 

 island, its haunts are on the sand-hills of the coast, among 

 which Formica emarginata swarms. The Dryinus, which is 

 not dissimilar in form and color, moves among them distin- 

 guished by its hitching gait, produced by the enormous length 

 of the tarsi and trochanters of its forelegs; it can run pretty 

 fast, however. * * * j witnessed an occurrence which 

 shows that it is not always quite amicable. Four ants were 

 bearing off one of the Dryinii quite alive and vigorous, though 

 not able to struggle much in their grip; my approach disturbing 

 them, three scampered off, but the fourth, more determined, 

 held on; the Dryinus however, as soon as she got fair play, 

 showed fight, and though her small jaws seemed ill calculated 

 to match those of the ant, the battle was maintained without 

 any visible disadvantage. * * * " Perkins (1905) says 

 that '' Paranteon no doubt has special habits; for the sluggish 

 hopper that it affects, forms flocks of greater or less extent, and 

 excreting much honey dew, is invariably covered with swarms 

 of ants, usually a moderate-sized species of Formicidce. The 

 Paranteon bears some slight resemblance to the ant in appear- 



