SYRPHIDAE OF MAINE. 169 



A female of PJatychirus perpallid-us, taken about wild mus- 

 tard and pea vine on August 3, 1916, deposited about 100 eggs 

 in the laboratory August 4 and 5, which began hatching on Au- 

 gust 7; the egg stage occupying about three days. The larvae 

 were fed on Aphis cornifoliae Fitch which they took in prefer- 

 ence to certain other species offered. They appeared to be full 

 grown by August 21, but did not begin pupation until August 28. 



This species was of particular interest because the genus 

 seems not to have been definitely recorded as aphidophagous in 

 the larval stage, although Professor J. W. Folsom 1 suspected 

 from the presence of the adults of P. quadrates Say about clover 

 aphids that they might have developed on them. 



According to Verrall 2 , P. scutatus, an European species of 

 the genus, "is said to have been bred from rotten fungi." 



I have recently taken males and females of P. scut at us, at 

 Orono, about spirea infested with Aphis spireacola. The females 

 oviposited in the laboratory and the larvae from these eggs are 

 at the present writing feeding contentedly on these aphids. So 

 that it may be doubted if the larvae of this species developed on 

 rotten fungi. 



Egg (Fig. 11. A). The length of a dozen eggs measured, ranged from 

 1.025 mm. to 1.085 mm., with an average of 1.046 mm. ; the maximum width 

 varied from 0.232 mm. to 0.256 mm. with an average of 0.244 mm. An 

 unusually elongate, straight-sided egg, almost cylindrical and more than 

 four times as long as its greatest diameter, instead of about three times, 

 as is usual in this group. The sculpturing of the chorion is similar to that 

 of such species as Syrphus americana, Sphaerophoria cylindrica, Allograpta 

 obliqua, and others, consisting of irregular elevated bodies surrounded by 

 irregularly radiating elevated arms. There are about forty such elevated 

 bodies the length of the egg. each measuring from 0.025 mm. to 0.045 mm. 

 in length and each surrounded by from 15 to 20 short, thick arms. 



In captivity the female deposited the eggs in a somewhat 

 characteristic manner, to some extent similar to that of Melan- 

 ostojiia mtllinum* three or four being ranked side by side; but 

 also with a strong tendency to place the eggs end to end. As 

 many as four were so placed in a. line with the ends contiguous, 

 suggesting very much in their arrangement a string of sausages, 

 (See Fig. 11, A). Whether this same habit prevails in the field 

 I am unable to say. 



'Univ. 111. Agr. Exp. Sta. Bui. 134, 1909. 

 'British Flies, Vol. VIII, p. 263. 

 8 Me. Agr. Exp. Sta. Bui. 253, p. 228. 



