AND ON THE VIVIPAROUS HABIT OF OTHER DIPTERA. 457 



1. I have prepared and examined one of the Phorocera cap- 

 tured at Hersea in August, and I cannot find any trace of larvae. 

 The gravid insects were captured in the month of June in a 

 garden in South Hampstead. These facts throw further light 

 on the life -history, as they suggest that the Her sea captures 

 had been recently hatched out, a supposition well supported by 

 their beautiful condition, and were then preparing to breed ; 

 finally making an attack on some late autumn caterpillar, spend- 

 ing the winter as pupae in the host, and appearing and mating 

 early in the spring. This accounts for the several species of 

 Lepidoptera that are attacked. 



2. I have also found larvae in the female of Blepharidea vul- 

 garis, Fin. I counted fifty-five in the abdomen of my prepara- 

 tion, but there are probably at least ten more. They are much 

 serrated on the surface, and have characteristic jaws with the 

 distal end blade-like. The imago has been bred out of Plusia 

 gamma, L. (Silver Y moth), one of the commonest species {Die 

 Fliegen, vol. i. p. 458). 



Explanation of Plate 36. 



Fig. 1. Diagram of the abdomen of the female of Phorocera 

 serriventris Rnd. ; lateral view to show the relative 

 position of the parts. All the setae and hairs are 

 omitted, a, hook ; b, serrated plates. 



2. Jaws of larva of P. serriventris to show the appearance 

 as seen with low powers when viewed through the 

 cleared plates of the abdomen ; lateral view. 



3. The same, seen in another position. 



4. Jaws of larva of Olivier a lateralis, F., seen in the same 

 manner as Fisr. 3. 



5. The structures and spiracles at the anal end of the 

 abdomen of P. serriventris highly magnified. Drawn 

 from a specimen taken out of the abdomen of the fly 

 and cleared in potash, s, spiracle. 



->•> 



if 



5? 



