22 MISCELLANEOUS FOREST INSECTS. 



Metathoracic wings. — The metathoracic wings are similar to those 

 of Dendroctonus, but are at once distinguished by the two branches 

 faintly connected with an evident cross-vein between the media and 

 cubitus. The writer has not made a sufficient study of the modifica- 

 tion of the veins in coleopterous wings to warrant anything more than 

 the provisional interpretations indicated in the recently published 

 figure (Hopkins, 1909, fig. 1). 



INTERNAL ANATOMY. 



The only parts of the internal anatomy that have been studied 

 in detail by the w'riter are the reproductive organs of both sexes, 

 which are of special interest, both from a systematic and from an 

 economic point of view. These present taxonomic characters of last 

 resort in the determination of the species. Those of the female are of 

 interest from the fact that it is claimed that individuals must attain 

 an age of several months before the ovaries are sufficiently matured 

 for the development of eggs; also, that a single copulation may 

 suffice for a long period; therefore it is important in our economic 

 studies to be able to readily recognize the sexes and the approximate 

 age of specimens collected at different times. The details of the 

 male reproductive organs are shown in Plates VIII to XI, and 

 require little explanation in addition to that given in the legends and 

 synopsis. It will be seen that there are specific differences in the 

 main body or stein (Plate XI), as well as in the fork (Plate X). The 

 organs of reproduction in a very young female are shown in Plates 

 VII and VIII, the parts of which are fully explained in the legends. 



The profile of the abdomen (Plates VII and IX, A), with the parts 

 in situ, shows the relation of the ventral and dorsal segments and 

 genital plates to the different parts of the reproductive organs, cer- 

 tain parts of which are evidently direct modifications of the ninth 

 and tenth dorsal and ventral segments. The figures are intended to 

 illustrate the main features and are in some respects subdiagram- 

 matical. 



SECONDARY SEXUAL CHARACTERS. 



Females. — In the females there are but 7 visible abdominal tergites, 

 the eighth being completely covered by the seventh, wliich forms the 

 pygidium. The beak is longer, smoother, and more slender than 

 in the males. The apical or seventh abdominal sternite is usually 

 shorter than the t ^receding sternites together, which are usually 

 less convex and more evenly punctured. The inner apical tooth of 

 the tibiae is also smaller. 



Males. — In the males there are 8 visible abdominal tergites; the 

 seventh is distinguished by the broadly retuse posterior margin, 

 while the eighth is prominent, with the apex broadly rounded, and 

 forms the pygidium. The abdominal sternites 3 and 4 are more con- 



