260 ANATOMY. 



The connecting muscles of the sternal processes exhibit no other 

 differences than that the smaller these processes become, the more they 

 also decrease in size. In general, these processes are very small in the 

 above orders, and it is thence, probably, that I could never discover in 

 them the furcate dorsal muscles, if these positively exist, which I feel 

 much inclined to doubt from the course of my observations. 



178- 



MUSCLES OF THE WINGS. 



The true muscles of the wings originate, like the lateral muscles, 

 from the lateral parts of the sternum, and pass on with pointed tendons 

 to the ribs of the wings. We find their extensor the most developed, 

 and their flexor the least so. 



The large extensor of the wing (extensor alee magnus) originates 

 inwardly from the lateral portion of the sternum, closely contiguous to 

 its internal process, and proceeds transversely to the large marginal rib 

 of the wing, inserting itself at a plate-shaped tendon, which hangs in 

 immediate connection with the base of this marginal rib. (PI. XI. 

 No. 3. f. 8. a.) If the anterior wings be the largest, as in the Hymen- 

 optera and Lepidoptera, the dorsal muscle of the anterior wing is 

 likewise the largest ; but if the posterior wings are wanting, as in the 

 Diptera, their extensor is also wanting ; and if both are of equal size, 

 as in the Libellulce and the majority of the Neuroptera, their extensors 

 also are of equal size ; but if the posterior wings are the largest, as in 

 the Coleoptera and Orthoptera, this is likewise the case with their 

 extensors. The extensor of the elytra is, for instance, very small, 

 whereas the extensor of the wing is of great size. 



The small extensor (extensor alee parvus) originates behind the 

 larger one from the lateral part of the sternum, or, frequently, from 

 its inflexion, formed by the cavity of the coxae, it runs contiguously 

 and parallel with the larger one as far as the articulation of the wing, 

 and likewise inserts itself, by means of a plate-shaped but smaller 

 tendon, to the second or posterior chief rib of the wing. 



The flexors of the wing (Jlexorcs alee ) are much smaller : they 

 originate from the parapleura, or, where this is not separated, from the 

 superior part of the lateral process of the sternum, and insert themselves 

 at the posterior margin, or upon the horny plates lying at the base of 

 the wing. In the Coleoptera, the flexor of the posterior wing consists 



