484 Miscellaneous. 



appears to me preferable to unite them to the preceding insects by 

 an intermediate o^roup, that of the PhryganidiS. Without discussing 

 their multiple affinities, without recording the retrogression which 

 their buccal organs undergo, I believe it necessary to insist on the 

 arrangements peculiar to their jaws. 



The somatic part corresponds, not to the maxilla, which is con- 

 fined to the base of the organ with the submaxilla, but to the galea 

 completed by a slender intermaxilla — a fresh manifestation of the 

 tendency sketched in Cephus, Megaihile, &c. The galea appears as 

 the directing section of the jaw, and this idea is still further accen- 

 tuated in the following groups. 



As far as the Lepidoptera are concerned, Savigny has shown 

 that their proboscis is the result of the union of the two jaws ; all 

 opinions to the contrary have been shown to be untenable. But 

 what is the mode of constitution of the jaws so transformed? What 

 part does each portion of the maxiliaj play in the construction of this 

 singular apparatus ? 



Observation shows that all the acting part of the organ arises 

 from the galea. Its base comprises the submaxillfe and the max- 

 illse ; greatly reduced and thrown back upon the sides of this base, 

 the palps take no part in the formation of the trunk properly so- 

 called. 



If one examines a maxillary stylet in the Hemiptera, one is 

 struck by its likeness to the mandible of a butterfly. In the two 

 cases the base corresponds to the same parts ; the lamellar region 

 (channelled, excavated, setiform, &c.) is essentially galear ; it is 

 easy to supply a demonstration of this, and certain Cicads especially 

 lend themselves to it. 



So for the Diptera, the types to be studied must be suitably 

 chosen. If we begin with the group of the Muscidse, as one usually 

 does, we are immediately brought face to face with difficulties 

 wliich will explain the divergences. They disappear when we con- 

 eider another family. 



The Eristalidae should be mentioned as especially offering forms 

 which link with the previous ones in establishing from another side 

 the passage to the singular mandibles of the Diptera, considered as 

 the most aberrant in this respect. I limit myself to a resume of 

 the arrangements presented by Eristalis tenax. On a base cleft in 

 two places there is inserted a tiny palp and a long blade, the latter 

 giving to the mandible its general configuration ; it represents the 

 galea, to which the intermaxilla is joined. 



So, in the Tabauidse, the Culicidae, &c., one recognizes the pre- 

 eminence of the galea, so secondary when one confines one's study 

 to the Borers. The exclusive study of these latter conduces to the 

 view that the maxilla is the fundamental portion, whereas nothing 

 could be more inexact. Morphographical analysis shows, in fact, 

 that the maxilla undergoes a true regression, whilst the mandible 

 acquires a new functional importance. This finds expression in 

 certain tendencies, proving progressively: — (1) elongation, of the 

 galea ; (2) fusion of the intermaxilla with the galea ; (3) reduction 

 of the palp. 



Thus a double organic balance shows itself: the maxillary region 



