NO. 7 MUSCULATURE OF COLEOPTERA DORSEY 7 



Two Other Orthoptera were studied, the cricket Gryllits assimilis 

 Fab. and the grasshopper Melanoplus differentialis (Thos.). In the 

 latter there are no essential differences in the musculature. In Gryllus 

 the muscle arrangement is practically the same as that found in 

 Periplaneta except for a few minor variations; the dilator muscle 

 group of the lahruni, 2, is absent, the ventral muscle of the labrum, 5, 

 is branched, and the muscle of hypo pharyngeal bar Y, 10, is not 

 branched. 



As a representative of Dermaptera, Anisolabis maritinta Gene was 

 chosen (figs. 4, 5, 6). The dorsal {anterior) m,uscle, 20, of the labium 

 (fig. 5), the ventral {posterior) muscle, 21, of the labium (fig. 5), 

 and the muscle of the prementum, 22 (figs. 5, 6), are essentially the 

 same as those in Periplaneta except that muscle 20 arises posterior 

 to muscle 21. The muscle of the hypopharynx, ip (figs. 5, 6), arises 

 centrally in the middle region of the mentum instead of on the ten- 

 torial structure as it does in the cockroach; this is an unusual origin 

 for this muscle, as it usually arises at some point on the posterior 

 tentorial structure. The insertion of this muscle, however, does not 

 vary. The flexor muscle of the glossa, 28 (fig. i), and the depressor 

 muscle of the labial palpus, 2^ (fig. i), are absent. The muscles of 

 the labrum, cibarium, and hypopharynx are similar to those of 

 Periplaneta. 



In Neuroptera, Corydalus cornutus L. adult and larval stages were 

 studied. The salivary muscles, in the adult form (figs. 8. 9), are 

 similar to those of Periplaneta; the anterior dorsal dilator muscle of 

 the salifarium, 75 (fig. i), is absent. The full complement of labial 

 muscles is present. The muscle of the hypopharynx, ip (figs. 8, 9), 

 arises laterally in the posterior region of the gula and is inserted at 

 the base of the hypopharynx, but not on the sides of the salivary cup 

 as is the case in Periplaneta. In addition to the usual compressor 

 muscle of the labrum, i (fig. 8), there is another muscle that arises 

 immediately posterior to muscle i and is inserted in the anterior re- 

 gion of the cibarium on the dorsal wall ; this muscle is probably only 

 a division of muscle i. The ventral muscle of the labrum, j, and the 

 dorsal muscle of the labrum, 4 (fig. 8), are of the general form and 

 arrangement. Of the dorsal dilator muscles of the cibarium, 5, 6, 7 

 (fig. 8), muscle 5 is represented by a single pair of muscles; muscle 6 

 consists of two pairs, and muscle 7 is also made up of two groups of 

 muscles on each side of the dorsum of the cibarium. The dorsal dila- 

 tor muscle of the anterior region of the pharynx, p (fig. 7), arises 

 laterad of the muscle of hypo pharyngeal bar Y , 10, instead of mesad 

 which is the usual way. 



