No. 637] 



PARASITISM 



159 



were evidently mistaken for moth-eggs. Premature ovi- 

 position is generally attributed to physical necessity in 

 relieving the pressure in the body, but here at least it is 

 accompanied by the outward appearance of instinct. 

 Whether this Chalcid tasted the strange new host is not 

 stated, but it is a common procedure among Chalcids 

 (Howard, '10) to tap the host with the ovipositor, and to 

 lap up the exuding body-juices quite independently of 

 egg-deposition. What her reasons for this may be are 

 obscure ; possibly it is to test the suitability of the host ; 

 perhaps to secure food, or she may even retain a specific 

 appetite for the kind of food consumed in her earlier 

 days. 



Marchal, Vayssiere ('07) and Loiselle ('08) have com- 

 mented upon the retarded development observed in cer- 

 tain Ichneumon-flies whereby emergence of some indi- 

 viduals was delayed a year. Such occurrences might 

 serve to bridge over the gap of a season when host in- 

 sects were scarce ; on the other hand, if the time were not 

 exactly twelve months it easily might lead to a new 

 ''trial" association in the absence of the proper host at 

 that season. 



That these factors might lead to divergence in habits, 

 I can not doubt, but hesitate to apply them to any con- 

 crete cases of aberrant habits. 



BIBLIOGRAPHY 



Aldrieh, J. M. 



1912. Note on Theronia fulvescens. Jour. Econ. Entom., Vol. 5, pp. 

 87-88. 

 Ashmead, W. H. 



1894. Descriptions of Two New Hymenopterous Parasites from Water 

 Beetles. Canadian Entom., Vol. 26, pp. 24-26. 



1900. Some Hymenopterous Parasites from Dragon-fly Eggs. Entom. 

 News, Vol. 11, pp. 615-616. 



Banks, N. 



1911. Cases of Phoresie. Entom. News, Vol. 22, pp. 194-197. 

 Baumberger, J. P. 



1919. A Nutritional Study of Insects, with Special Reference to 



Microorganisms and their Substrata. Jour. Exper. Zool., Vol. 



28, 1-81, figs. 18. 



