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BRUES. 



in size due to age at the time of parasitization. Such variation is 

 always more pronounced among the parasites of insect larvse than is 

 the case with egg-parasites where the food supply of each individual 

 parasite is more evenly apportioned {e.g., in the related family 

 Scelionidae). 



As can be seen from the diagrammatic sketches shown in Figure 1, 

 the variability in size of the gaster is quite noticeable, but not excessive. 

 The following segments (four to six) show enormous differences not 



Figure 1. Polymecus (Dolichotrypes) minor sp. nov. Diagrammatic views 

 in profile of the abdomen of a selected series of females. 



only in actual length but also in proportionate length in any selected 

 series. Of these, segments four, five and six are black and heavily 

 chitinized, while the seventh or apical one is membranous and almost 

 hyaline. Beyond it, extends the ovipositor and its two sheaths which 

 may be exserted to great length or very nearly concealed within the 

 body. Taken together, these elongated segments resemble the tele- 

 scopic arrangement of parts seen in many insects and other animals. 

 In fact the abdomen of all insects is built upon this principle as its 



