STTTDIES ON INSECT SPERMATOGENESIS. 397 



Table I, into -w-hich some errors have doubtless crept through 

 insufficient material, accidents of sectioning, or doubtful s\-non\-my 

 of the generic titles, ^"here the material was ob\'iously insufficient 

 or unsatisfactory the fact is indicated by a dash, and doubtful 

 points are marked " ?." It should be added that, like Montgomery, 

 I ha\"e as a rule recorded size differences only when they were reason- 

 ably ob\-ious. In other words, a case like Murgantia in which the 

 size differences are shght, might be overlooked, especiall\- if the 

 material was not first class. Furthermore, I have made no special 

 effort to detect lobes in which the spermatoc^-tes are unusually 

 small. This was because the differences in this respect are by no 

 means striking, — in fact are often rather difficult to make out even in 

 Euschistus if the material is poor,— and the value of the results 

 seemed hardly commensurate with the labor involved. 



The table gives in the first column the list of forms examined, the 

 nomenclature followed being that of Van Duzee ('17); in the second 

 column is given the number of lobes in the testis of a given species, 

 while the third and fourth columns give the index numbers of the lobes 

 in which unusually large or unusually small (where noted > cells occur, 

 these numbers being assigned in accordance with the plan pre\'iously 

 described (see Text-figs. lA and B). Comparisons were generally 

 made on spermatoc\tes in the late growth period, and exact observa- 

 tions on the mature sjjerm were usually impossible for ob^"iou5 reasons. 



Examination of Table I shows at once that far from being a phe- 

 nomenon unique to a single genus, the spermatic polxTnegaly is widely 

 distributed in the Family Peniatomidae, and is in fact rather more 

 common than rare. ^Montgomery's original idea is therefore erroneous, 

 and his failure to detect differences in some of the other genera which 

 he examined for this point is rather puzzling. Thus in our common 

 species of Brochymena the difference is very striking, though Mont- 

 gomery reported a general equality for this genus. Possibly a clue 

 is to be found in the case of Stzara, in which no dimegaly occurs in 

 the northern sp^ecies, hilaris, but a very noticeable one in the southern 

 species, viridula. At the same time it is interesting to note that ^ an 

 Duzee ('17) has now placed these two sp)ecies in different genera, 

 Nezara and Acrosternum. Doubtless the form which Montgomery 

 examined was Acrosternuvi (= Nezara) hilaris, in which absence of 

 dimegalv is also indicated bv mv obser\'ations. Further, in a number 

 of known cases the identification of forms studied by Montgomery 

 ('9S and '10) was not very critical, and the discrepancies may be due 

 in part to such errors. 



