PARASITES OF THE EARLY STAGES OF TABANIDiE. 



Hymenopterous Egg Parasites; Early Discoveries. 



Kollar (1854) is the first to mention an egg parasite of Tahanus. 

 From egg masses of Tabanus quatuornotatus collected at Wippach, 

 Austria, by Mann, June 25, 1854, there were observed to hatch not 

 only young Tahanus larvae but "also another completely developed 

 insect belonging to an entirely different order and family, a little 

 animal which belongs to the extraordinarily large and still inextric- 

 able army of the parasitic wasps (Ichneumonidae)." It was con- 

 cluded that, immediately after the Tahanus had deposited its eggs, a 

 parasitic wasp had appeared and deposited its eggs in those of the 

 Tahanus. Parasitic wasps were then known to develop in the eggs 

 of Lepidoptera, chiefly Bombycidae, and of various Hemiptera, but in 

 Diptera such egg parasites had not been observed (Kollar). The 

 length of one of these parasites is given as two-thirds of a line; the 

 size of the Tahanus eggs as one line in length, and one-seventh of a 

 line in diameter; Kollar thinks it probable that several wasps develop 

 from a single Tahanus egg, which is probably not the case.^^ 



On egg masses of a second species of Tahanus, collected by himself 

 at Dornbach, near Vienna, Kollar found a similar but specifically 

 different parasitic wasp, which was just ovipositing its eggs in those 

 of the Tahanus. In order to learn how much time was necessary for 

 the development of the wasp, Kollar kept the Tahanus eggs in a 

 small bottle closed by means of perforated paper, and obtained on 

 the fifteenth day several hundred wasps. From the number of 

 parasites he believed he was justified in assuming that from one 

 Tahanus egg more than one wasp may develop. However, the num- 

 ber of eggs in the cluster had been said, for Tahanus quatuornotatus 

 Meig. to be 350 to 400, and it is not said whether the number of 

 wasps hatching exceeded the number of eggs. 



The two sexes of the parasites could be differentiated ; a description 

 and figures were promised but apparently have never been published. 



^' See Hart (1895), Phanurus tahanivorus, p. 272. 



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