2686 Insects. 



observed in the mandible of any insect. No suggestion can be raised as 

 to the character of the palpi, seeing they have no kind of connexion 

 with the labium, which, as already described, exists in an evident 

 although very diminutive state, and situate as distant as possible from 

 the insertion of the palpi : they are therefore maxipalpi. 



The form of maxilla which I have described as characterising Sty- 

 lops is not of uncommon occurrence. In Lepidoptera it occurs fre- 

 quently among the Bombyces : in Diptera we find it in the Tabanites : 

 in Hymenoptera it exists in some of the bees ; but in these three 

 classes there is so great a development of the labial apparatus that 

 the similarity is not carried out, ceasing with the organs in question : 

 in Orthoptera and Neuroptera I recollect nothing analogous to the 

 maxillae of Stylops, while the Hemiptera have all the cibarian organs 

 linear and setiform, fully and normally developed palpi — like those of 

 Stylops — being invariably absent throughout the class : in Coleoptera 

 such maxillae are of very uncommon occurrence ; still they are occa- 

 sionally to be found, although, in every case which suggests itself for 

 comparison, the Coleopterous insect seems not merely to imitate, but to 

 caricature, the linear, lancet-like maxillae of Stylops. The first insects 

 I shall cite are two North-American Telephorites, described by Hentz 

 under the names of Chauliognathus marginatus and C. bimaculatus, in 

 which the maxilla and maxipalpus are constructed precisely on the 

 same plan as in Stylops, the only notable differences being that the 

 Chauliognathi have a greater length of lacinia and a greater number 

 of joints to the maxipalpus ; but evident as is the similarity between 

 the maxillae of Chauliognathus and Stylops, it is still more striking 

 between the latter insect and three species of parasitic Hormocera, the 

 very group with which I have shown that the economy of Stylops 

 presented so exact an analogy : these insects are Macrosiagona dimi- 

 diata (one of the Mordellites), and Nemognatha and Gnathium (two 

 genera allied to Cantharis) ; and it is worthy of remark, as affording 

 some colour to this view of the case, that in all these genera the pe- 

 culiarity is said to be confined to male insects. After a perusal of these 

 observations my readers will, I think, be willing to admit that however 

 slight the tendency of this imperfect mouth towards a Coleopterous 

 type, it certainly has less tendency towards any other class. The 

 other parts of the head require a few words. 



The eyes of Stylops are remarkable. Those who have studied the 

 eyes of insects with a view of generalizing phenomena must have ob- 

 served that these organs are very largely developed throughout the 

 Diptera; the head has become almost all eye: the accurate observer 



