340 Mr. Westwood on the Sexes in Cetoniidae. 



and have discovered analogous differences in several other 

 species. In Steplumorrhma (Burm.) guttata, Oliv., the male 

 has the mando unarmed, whilst it is furnished with a short 

 acute horny tooth in the female. 



In Jumnos Roylii [Cetonia R., Hope, in Prof, lloyle's work 

 on the Himalaya), the male* has the apex of the inner lobe of 

 the maxilla scarcely produced beyond a straight liiTe ; whereas 

 in the female it is armed with a strong curved tooth. In the 

 Rhomborrhince [Cetonia opa/ina, Mellii, &c.) the males have the 

 lower lobe almost unarmed, whilst in the females it is strongly 

 hooked. In Cetonia [Coryphe) elegans both lobes of the 

 maxillae are obtuse in the male, but much more acute in the 

 female; whilst in C {Trigonopliorus, Hope) Hardw'icVii the 

 apex of the lower lobe is much more acute in the female than 

 in the male, although conical and corneous in the latter. 



In Goliathus [Dicronorrhina, H.) micans, on the other hand, 

 the lower lobe is unarmed in both sexes ; and the same may 

 be said to be the case in the three fine African species unknown 

 to Gory, Percheron, and MacLeay, which constitute a small 

 group, to which I have given the name of Tmesorrhina (Arc. 

 Ent., pi. 19), except that in the females the mando is slightly 

 produced into a small point. In Coryphe MacLeaii the mando 

 is produced in both sexes into an angulated point, rather more 

 acute in the female than in the male ; but in Coryphe umbonata 

 and Diceros bicornuta, I have not found any distinction in the 

 maxillae of the opposite sexes. The same is also the case in 

 the interesting African Schizorrhina cyanea, Oliv., only here 

 the maxillae are of different form. 



To those who have investigated the structure of the trophi 

 of insects, a difference of the kind, mentioned in this and my 

 former notice as occurring in some Lucanidce, will be consi- 

 dered interesting, because, of all the organs, none exhibit so 

 constant an uniformity of structure as the maxillae. " Maxil- 

 1am constantissimam invenimus, vix in congeneribus variat" — 

 and " Maxillse et labium tunc constantissima, semper simil- 

 lima," observes Fabricius ; and Mr. MacLeay places it in the 

 least vai'iable position in his table of the variation of the or- 

 gans of insects (' Horae Ent.,' p. 5). The only notice I have 

 found of a sex\xal difference in this part is in the genus Ne- 

 mognatha, belonging to the Heteromerous Colcoptera, where 

 the upper lobe is exceedingly elongated, which character has 

 been surmised to be sexual (K. and S., Introd., vol. iii. p. 317). 



The discovery of this sexual distinction will render neces- 



* The male of this insect tigrees with Jumiios Ruckerii , as figuved in 

 the Transactions of the Entomological Society, in the curious toothing of 

 the fore-tibiae. It is the female which is figured in Ur. Royle's work. 



