LARVAL HEAD OF SOME CHIRONOMIDAE GOUIN 



195 



nomian larvae (Gouin, 1946a, 1946b), these two types being in this 

 particular rather similar. The larval tracheal system is more reduced 

 in Chironominae larvae than in the others. 



J'IPrm 



Fig. 13. — Macropclopia cf. nebulosa Mg. 



Part of a sagittal section passing on the level of hypochilan combs (P Hch). 

 It shows the connections of the hypochilum (Hch) and the combs with the 

 cranial wall, the insertion of the premental muscle (M Prm), some fiber groups 

 of the pharyngeal dilators (M Ph dl), and the muscle Mrao. The mandible 

 shows an innervated seta ; the maxilla shows an innervated part of palpus 

 {Pa Mx) and the ventral basal sclerite (cardo p.p.) ; the tendon of the lacinial 

 muscle (TLac) is tangentially cut. 



SOME REMARKABLE RELATIONSHIPS IN THE 

 GNATHAL REGION 



After this detailed study of the structural types of Orthocladiinae, 

 Podonominae, and Tanypinae and that of Chironomidae (Gouin, 

 1957), I shall attempt to deduce some outlines of the relationships 

 between the organs of the gnathal region. Though the data of authors 

 are unfortunately rather rare, two aspects can be evoked. 



RELATIONSHIPS BETWEEN THE MANDIBLE AND THE HYPOCHILUM 



In the lower Nematocera larvae {Trichocera, Mycetobia, Rhyphus), 

 Anthon (1943) describes a conformation of the mandible; he con- 

 siders it as being divided into two segments, of which the distal one 



