246 NEWMAN ON THE 



dibles do not, move horizontally." The maxillary line M O L in 

 the diagram divides the seven classes agreeably to this definition, 

 leaving Clairville's Mandihulata on one side, and his Haustel- 

 lata on the other. In Neuroptera the Phryganina and Ephe- 

 merina, whose mandibles are obsolete or rudimental, and possess 

 no motion, range with the Lepidoptera, &c. ; and the Pet-lina, 

 Hemerobiina Bind Panorpina, which have strongmandibles, formed 

 for active employment, range with the Orthoptera, Coleoptera, 

 and Hymenoptera. It is here to be observed, that the supposed 

 typical or central group of Neuroptera, and therefore of insects, 

 is decidedly mandibulate. The maxillary line, consequently, 

 cannot pass directly through the centre of this class. Here, as 

 in the prior figure, the line has more decided reference to the 

 circumferential classes than to the central. 



It has been, I trust, fully shown in my second letter on 

 Osteology, that " the mouth of insects is not in its differences 

 confined to two plans." The mouth in each class differs widely, 

 and the transition of the various parts from one form to another 

 is to be traced with the greatest ease. Yielding, however, to 

 the trammels of the Maxillary dichotomy, in order to show that 

 it is in perfect consonance with the Septenary System, 1 will 

 attempt to compile characters by which to distinguish from 

 each other the contents of the classes separated by the maxil- 

 lary line. 



Mandibles fully developed, strong, corneous, possessed of hori- 

 zontal motion, formed for mastication : maxillae corneous, pos- 

 sessed of horizontal motion, occasionally formed for detrition or 

 mastication. 



Such is preeminently the character of the insects comprised 

 in the class Coleoptera. As we pass right and left, we find 

 these characters strongly exhibited in the Orthoptera and 

 Hymenoptera. In a portion of the Hymenoptera, the bees, 

 the maxillse evince symptoms of departure from the typical 

 character. They become leathery, lengthened, linear, and 

 united with the ligula form as in Diptera, Lepidoptera, and 

 Hemiptera. a suctorial tube. Above the maxillary line the 

 following characters may serve :■ — 



Mandibles and maxillae linear, weak, leathery, often elongate, incapable 

 of horizontal motion, and also of mastication or detrition. 



