Anatomy of the Male Genital Tuhe in Goleoptera. 589 



narrow strip of membrane ; their inner aspects flattened and ad- 

 pressed. Median lobe apparently not passing between the lateral 

 lobes. 



This is very different from any other of the forms 

 we have examined. The relationship of the median lobe 

 and the lateral lobes would appear to be very unusual, 

 but having only one specimen at our disposal this is not 

 very clear. 



Rliizotrogus solstitialis. 



Of the same type as Melolontha. Median lobe medium size, 

 membranous, supported by two thin sclerites. Lateral lobes large, 

 broad, joined together to near their tips and forming a tube. 

 Basal-piece not quite so long as the lateral lobes, chitinous on dorsal 

 side but membranous on ventral. Internal sac large. 



Anoxia orientalis. 



Median lobe small, chitinous on each side, with two long 

 median struts. Lateral lobes very large, long and curved at 

 points ; on ventral side they are consolidated for about one-fourth 

 of their length near the base ; on the dorsal side the basal three- 

 fifths are consolidated together. Basal-piece tambour-like, some- 

 what shorter than the lateral lobes. Internal sac fair size, no 

 chitinous armature. 



Melolontha. vtilgaris. 



Median lobe fair size but membranous, except for a narrow 

 strip of chitin along each side, proceeding into basal-piece as two 

 median struts. Lateral lobes long, narrow, and curved, with the 

 tips slightly expanded ; joined together at their base on ventral 

 and dorsal sides with a membranous connection nearly to their 

 tips. Basal-piece tambour-like, forming a large curved sclerite on 

 dorsal side, the ventral side membranous. Internal sac large and 

 complex, covered with small hairs but bearing no chitinous 

 armature. 



The student should refer to Straus-Durckheim's immortal 

 work on Melolontha. It will give him a good idea of the 

 genital tube in Coleoptera, as well as a knowledge of 

 the details of this species. He uses the term " tambour ' 

 for the large basal-piece of the aedeagus, and we have 

 used it also in the sense of a general resemblance to 

 Melolontha in the form of this part. The tambour shape 

 does not exist in Trox, and Amphicoma shows a very great 

 modification of it. 



TRANS, ENT.SOC.LOND. 1912. — PART III. (DEC.) RR 



