396 



BOWEN. 



mere chance variations was proved by examina- 

 tion of 41 testes of Enschistus sp., and 4 testes of 

 E. tristigmus, in all of which the conditions were 

 identical. Certain other pentatomids {Brochy- 

 mena, Perillvs, Nezara, Cosmopepla, Mormidea, 

 Trichopepla) were also examined, but in no case 

 did Montgomery find "such constant size differ- 

 ence," or at least it was "much less appreciable." 

 In his final paper on Etischishis , Montgomery ('11) 

 intimated that he had made further observations 

 on the phenomenon of "dimegaly" in Euschistus, 

 but these were never published and the subject 

 has not since been reexamined. 



My attention was attracted to this problem by 

 the discovery that in Murgantia size differences also 

 occur, very much less conspicuous than in Eiischs- 

 tus, giving rise to cell generations of two sizes, — the 

 spermatocytes in lobes 1, 2 and 5 (Text-fig. 1^) 

 being small or "normal," in lobes 3 and 4, some- 

 what larger. Text-figures 2-1 give an idea of these 

 size relations in the primary spermatocytes, which 

 may be compared with the corresponding cells of 

 Enschistus shown in Text-figures 2-II. It was 

 found subsequently that the expected two sizes of 

 sperms (Text-fig. 3) were formed by processes dif- 

 fering somewhat superficially, but as constant as 

 the dimegalous condition itself. These facts, taken 

 together, aroused the suspicion that this whole 

 phenomenon might not be so unique as Mont- 

 gomery had thought, and I accordingly undertook 

 to make as complete a survey as possible of the 

 Family Pentatoviidae with respect to this particular 

 point. Such an examination was made possible by 

 the fact that Professor Wilson's preparations, — re- 

 ferred to above,^ — included a large number of penta- 

 tomids of which the majority had received depend- 

 able identification. My results are tabulated in 



Figure 3. Mature sperms from the vas deferens of 

 Murgantia histrionica (x965). (Smear preparation; osmic 

 fumes-hematoxyUn.) A, from the small or normal gen- 

 ^ erations; B, from the large generations. 



