210 



INTRODUCTION. 



apparently gone back to Erichson's system and regards the 

 Lamellicoristia and Scarab.eidjl; as synonymous. Leconte and 

 Horn (Classif. Col. North America, 1883, p. 248), observing that 

 the MelolonthiDjE and their allies were intermediate between 

 the Laparosticti and the Pleurosticti, added a third division 



MeLOLONTHID^E. 



Both Erichson's and Leconte and Horn's divisions are un- 

 satisfactory, for, as Arrow has pointed out (Trans. Ent. Soc. 

 Lond. 1909, p. 480), the division of the ScARABiEiDiE into 

 Laparosticti and Pleurosticti according to the situation of the 

 spiracles does not correspond with any sharp natural line of cleav- 

 age, as there are not only two but several types which pass one into 

 the other, and the point of division must necessarily be arbitrary. 

 Recently, too, Dr. Ohaus (Deutsche Ent. Zeitschr. 1909, p. 427) 

 has pointed out that Aclopus brunneus is Laparostict in the male 

 and Pleurostict in the female. At the same time Arrow allows 

 that the distinction is useful, and gives the following table for the 

 Laparostict Scarab^id^e, that is to say, those subfamilies in 

 which the posterior spiracles are situated in the membrane between 

 the dorsal and ventral plates of the segment : — 



I. Antennal club of more than three joints. 



i. Antennas eleven-jointed Pleocominje. 



ii. Antennas eight-jointed Pachypodin^:. 



II. Antennal club composed of three joints. 



i. Labrum and mandibles horizontally extended, 



flattened. 



1. E}^es divided in front. 



A. Labrum as long as mandibles Aclopiinle. 



P. Labrum shorter than mandibles. 



a. Antennas eleven-jointed Geotrupinje. 



b. Antennas ten-jointed. 



a*. Antennal club telescopic, joints 



cup-shaped Hybosorin^e. 



/>*. Antennal club simple, lamellate. 

 a\. Stridulating plate in hind coxal 



cavity Taurocerastin^. 



if. Stridniating plate on hind coxa. OitPHNiNiE. 

 b. Antennas nine-jointed Chironin.e. 



2. Eyes entire Ochodjeinje. 



ii. Labrum and mandibles not horizontally 



extended. 



1. Antennas ten-jointed. 



A. Labrum very small Idiostomin^e. 



B. Labrum large Troginje. 



2. Antennas eight- or nine-jointed ; labrum 



reduced and concealed. 



A. Hind tibia two-spined ; mid-coxas con- 



tiguous Aphodiinje. 



B. Hind tibia one - spined ; mid - coxas 



separate Coprinje. 



All the above subfamilies, with the exception of the Pleo- 

 cominje, Pachypodenve, Aclopikje, Tatjrocerastii^e, and Ibio- 



