228 



THE ENTOMOLOGIST. 



the rarer male may appear in the spring after hibernation. On 

 gooseberry. 



*Pristiphora ruficofnis 01. — All eggs appear fertile ; failed' to 

 rear larvae. On hawthorn. 



Pteronidea pavida Lep. — Specimen 1 : All the 62 eggs col- 

 lapsed and did not hatch. On willow. Specimen 2 : A batch 

 of 56 eggs ; all except 1 fertile ; larvae hibernating 1921-22. 

 On willow. 



-'Platy campus luridiventris Fall. — Specimen 1 : 2 larvae from 

 7 egg-holes ; failed to rear. On alder. 



I failed to obtain parthenogenetic eggs from 5 specimens of 

 Amauronematus vittatus Lep., using alder and birch, the plants 

 upon which the larvae had been found and reared. I am 

 investigating the matter of food-plants of this species, which is 

 regarded as attached to willow. 



The specimens starred are not recorded as parthenogenetic 

 in the lists of Cameron (2) and Enslin. 



Eegarding the alder species N. fnscipennis, luteus and 

 P. luridiventris, which lay deeply in relatively hard plant-tissue, 

 it is impossible to say whether each egg-hole made contained an 

 ■egg or not. From my observations on the insects while they 

 went through this performance, however, I should say that each 

 hole did contain an egg. 



J 



Number of Parthenogenetic Eggs Laid and the Rate 

 of Laying. 



Species. 

 A. serotinus 



A. pallipes 



JV. fnscipennis 



N. luteus . 



P. obductus 



P. pallipes 

 P. ruficomis 



Total laid per 

 insect. 



61 from 2 flies 

 55 „ ' „ 



6 



10 



25 



20 



20 



10-12 



80 from 3 flies 



16 



Individual rate of laying. 



3 in 7 days ; 4 in 10 days ; 6 in 



14 days. 

 Spec. 1 : 12 in 30 minutes. 

 „ 2: 3 „ 30 

 „ 3: 8 „ 30 

 Specs. 1 and 2 : 61 in 6 days. 



„ 3 „ 4: 55 „ 5 „ 

 Spec. 1 : 6 egg-holes in 24 hours. 

 „ 2:10 •„ 15 „ 



„ 3: 25 N „ 24 „ 



(In the green stalk of leaf, egg 

 laid in 4 minutes ; in harder 

 brown stalk, 7 minutes.) 



Spec. 1 : None. 



Spec. 2: 12 egg-holes in 24 hours; 



20 in 48 hours. 

 Spec. 1 : 6 in 24 hours. 

 ,, 2 : 10-12 in 7 days. 



