340 PARASITISM 



eggs being lodged on parts of the integument too thick for 

 penetration. 



Pantel's Group III. comprises those Sarcophagidge which deposit 

 larva) on the bodies of their hosts. They are true viviparous 

 flies with many parasitic species and are now often regarded as a 

 sub-family of the Tachinid?e. A good example of supra-cutaneous 

 larviposition is afforded by Sarcophaga kellyi which deposits its 

 larvae beneath the folded wings or on the abdomen of Melanoplus 

 grasshoppers. The young parasites quickly bore their way through 

 the inter-articular membranes and lead an endoparasitic life 

 (Kelly, 1914). 



There are again other Tachinids, forming Group VI, of Pantel, 

 which are ovo- viviparous. Their eggs are thin-shelled, and the 

 larva? issue either in the uterus of the parent or almost immediately 

 after oviposition. They differ from those mentioned in Group A 

 in that the integument is devoid of chitinous armature, and they 

 are ill-adapted for prolonged exposure. Many species of Tachinids 

 come under this category, but it is probable that actual larvi- 

 position occurs less frequently on the host itself, and more often 

 eggs are deposited which hatch almost immediately. Townsend 

 has pointed out that certain Dexiine species parasitise insects 

 living in concealed situations, such as leaf-miners, wood-borers, 

 etc. The flies penetrate into the burrows of these concealed 

 hosts depositing their larvae in their immediate proximity. Such 

 unarmoured parasites, finding themselves in confined spaces, 

 have only short distances to traverse before discovering their 

 hosts. Among ovo-viviparous Tachinids, species of Sturmia, 

 Exorista, Thelaira, Bucentes, Plagia, Voria, and other genera are 

 enumerated by Baer (1920) and by Thompson (1926). 



Group D. In this group are included the greater number of 

 the parasitic species of Hymenoptera and certain of the Diptera, 

 including the Pipunculidse, Conopidse, the Agromyzid genus 

 Cryptocho'tum and a few of the Tachinidae. 



Among endoparasitic Hymenoptera the eggs may be inserted 

 either within the eggs, larvae, pupae or adults of the hosts con- 

 cerned. The Mymaridae, Trichogrammidae, Scelionidae and many 

 Platygasteridae are essentially egg-parasites completing their 



