05 



THE NATURAL ENEMIES OP THE FROGHOPFER. 



PARASITES OF THE EGG. 



The Vermilion Parasite {Olignsifa girauUi, Crawford). 



This egg-parasite was first discovered by Guppy in December, 1912 

 and was described by J. C. Crawford (Canadian Entomologist XLV 

 (1913) p. 311-312) from specimens sent by Urich. 



It is a minute Chalcid about 0-6mui. (one-fortieth of an inch) in 

 length, with the body bright vermilion-red except for a band round the 

 base of the abdomen which is wliite. 



This insect lays its eggs in the eggs of the froghopper and its grub 

 feeds inside the froghopper egg on the contents, which suffice for the 

 complete development of tlie parasite. 



Its development is complete within about thirty days (Qrich 1913 D.) 

 and the female as soon as it has emerged can proceed to lay eggs 

 without the iiecessity of pairing with a male. In fact in Trinidad the 

 male has up to the present never been seen, but in Panama I obtained 

 one or two specimens of it in a locality where females were very 

 abundant. 



The parasite appears to bo able to carry on its life cycle throughout 



most of the year in localities which are drier than is necessary for the 



breeding of the froghopper, and specimens may be obtained in the dry 



' season in spots wliere the froghopper lias temporarily ceased to breed. 



It is on the other hand probably adversely affected by heavy rains. 



There have been no observations on the percentage of parasitism in 

 the field, but Kershaw under artificial conditions was only able to obtain 

 an infestation of about five per cent. 



It is very probable that it has some alternative host, as it exists 

 commonly in localities where the froghopper is rare. I have been able 

 to get adults to oviposit in eggs of leaf-hoppers (Jassidis) but so far have 

 not succeeded in breeding it through in these eggs. 



It is common throughout Trinidad in all suitable localities and 

 abroad I have found it in British Guiana, Tobago, Panama, and Costa 

 Rica, parasitising various species of the genus Tomaspis. 



In Panama it was very abundant, and, as mentioned above, males were 

 found, but the discovery of it over such a wide range leaves no doubt 

 that it is native to Trinidad and is not likely to increase naturally much 

 above its present limits. 



Urich (1913 A & D) has made attempts to introduce it into the sugar- 

 cane fields by bringing grass from other localities where it is known to 

 be common, but while the method is theoretically correct it has not 

 been possible yet to demonstrate an^' practical result following from it. 



The Trash-Coloured Parasite {Faraphelinus tomaspidis, 

 Howard). 



This parasite was also discovered by Guppy in January 1913 in the 

 Princes Town district and was described by Howard in 1914 (Proc. 

 Ent. Soc. Washington XVI (1914) p. 81-82). It is a uniformly brownish 

 insect of about the same size as the vermilion parasite, and like it, lives 

 during its larval life on the contents of a single insect egg. 



