342 Mr. Lubbock on the 



a certain extent, they resemble the imago, having the various 

 limbs enclosed in distinct sheaths, and folded upon the breast. 

 The perfect insect escapes from this state by means of a slit down 

 the back." 



As we have seen, the development of Lonchoptera does not 

 answer to the above description, and the genus must, therefore, be 

 removed from the Tany stoma altogether. The pupa of Platypeza is 

 not known, but it is probable that this genus, and perhaps one or 

 two others, must eventually follow the fortunes of Lonchoptera. 

 Scenopinus, on the contrary, whose transformations have been 

 described by Bouche, and more recently by L. Dufour (Ann. Soc. 

 Ent. France, 2 Ser. T. 8, 1850, p. 493—6), belongs truly to the 

 Tanystomatous type. 



Our knowledge of the Diptera is not yet probably so advanced 

 as to enable us to arrange them correctly ; the numerous forms 

 which still remain undiscovered, and the many points in their 

 metamorphosis and anatomy which have yet to be described, will 

 assuredly modify our views as to their classification and mutual 

 affinities. I feel also strongly that my own acquaintance with the 

 subject does not justify me in expressing any very decided opinion. 

 I may, however, be permitted to suggest that the true position of 

 Lonchoptera is among the Notacantha, not very far perhaps from 

 Sargus. Not only does the metamorphosis belong to the type 

 which is characteristic of this group, but the larvae of the two 

 genera are by no means dissimilar. It must be confessed that 

 the perfect insects of these two genera differ in many points, but 

 not in more probably than those which already distinguish Lon- 

 choptera from the Dolichopidce and Platypezidce. 



Intkrnal Anatomy. 



My principal object being the determination of the species to 

 which my larva belonged, I only sacrificed one specimen for 

 anatomical purposes : when the first imago of Lonchoptera made 

 its welcome appearance, only one larva and one pupa were 

 living; these I immediately put into spirits of wine. 



Having therefore had but two larvae for dissection, and one of 

 these being in an unfavourable condition, I cannot give anything 

 like a complete account of the internal anatomy. Moreover, the 

 digestive organs of my two specimens were so dissimilar, that in 

 all probability one of them was about to become a pupa. 



The disposition of the tracheae offers no remarkable pecu- 

 liarities. As in the larvae of other allied Diptera, there are four 

 spiracles only, two on each side ; one at the posterior extremity, 



