48 



THE CANADIAN ENTOMOLOGIST. 



NOTES ON THE- BREEDING OF TROPIDOPRIA CONICA 



FABR.* 



BY G. E. SANDERS, DIVISION OF ENTOMOLOGY, OTTAWA. 



In carrying on some dipterous experiments in the Division, in August, 

 19 TO, many of the puparia of Eristalis tetiax Linn, were found to contain 

 the well-known parasite TropidopJ'ia conica. About forty per cent, 

 collected under natural conditions in x\ugust and September were found 

 to be infested, giving on an average 35 adult parasites to each puparium. 

 The highest number from one puparium was 46, and the lowest 21. 



Emergefice. — This takes place through one or more round, somewhat 

 jagged holes, about 3 mm. in diameter, cut in the side of the puparium. 

 The holes are cut by the adult after they have completed their transforma- 

 tions. All the parasites in one puparium appear to complete their trans- 

 formations at the same time, showing no indication of a partial retarded 

 development as is so often found in similar parasites. 



Afaiing.-^hhouX. three hours after emergence many pairs were seen 

 together, apparently in coitu ; closer examination, however, showed that 



this was not the case. The male had 

 placed himself firmly upon the dorsal 

 surface of the female, and with his two 

 front tar?i had caught hold of the 

 antennae of the female and drawn them 

 upwards and backwards until they lay 

 nearly perpendicular, one on each side, 

 close to the fore part of his thorax. 

 The antennse of the male were thrown 

 back so that the sense organ, or gland, 

 situated on the fourth antennal joint, 

 as shown in figure 2, lay directly 

 against the antennal club of the female. 

 This organ was being passed quickly 

 up and down the female's antennal 

 club, and was evidently intended to 

 excite the female sexually ; the wings 

 of the male were raised and fluttered 

 continuously during the process. Often 

 this means of excitemeijt continued for three minutes, but more often it 



A B 



Fig. 2. — Proximal portions of antenna; of 



Tropidjpria conica (x 45). A, right 



antenna ; B, left antenna. 



"Scientific Contributions from the Division of Entomology, Ottawa. 

 February, 1911 



