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But the larvíc of Coleóptera, on account of the great variety of 

 form which they exhibit, are admitted to be of exceptional 

 morphological interest, and the hypopharynx, with its associated 

 structures, has received but slight attention from students of 

 their anatomy. As is well known, the larvae of beetles furnish 

 a series showing transition from the " campodeiform " to the 

 "cruciform" type, and many students, following Brauer 

 (i86g), have used these facts as an argument that, in the 

 phylogeny of the Insecta, the active, armoured larva must 

 be more primitive than the legless grub, and that there must 

 have been, in the course of insect evolution, an increasing 

 divergence between the imaginai and larval stages. A ". campo- 

 deiform " type of beetle-larva might offer, therefore, promising 

 material for study, and in the root-eating grub of Dascillus 

 cervinus — numerous specimens of w^hich have lately come 

 into my hands through agricultural inquiries — a type is found 

 in which the larval mouth-appendages differ far less than is 

 usual from the corresponding parts in the adult. In this larva, 

 for example, the maxilla has the typical parts — cardo, stipes, 

 lacinia, galea, and palp well-developed ; there is very httle 

 of that reduction which characterises the maxilla of an adcpha- 

 gous larva. 



In collaboration with my former pupil, Miss M. C. Mac- 

 DowELL, I have made a careful examination of the hypopharynx 

 of the Dascillus lar\a. comparing with it the corresponding 

 structures in the aquatic larva of Helodes (which belongs also 

 to the Dascillidie) and in the well-known fleshy grubs of two 

 Scarabieid genera — Phyllopertha (the Garden Chafer) and 

 Geotrupes (the Dor Beetle). Our descriptions and figures have 

 recently been published (1912). In the Dascillus larva, we 

 find, on the dorsal surface of the hypopharynx, two prominent 

 lobed sclerites, which bear each a curved row of strong, blunt 

 teeth. These sclerites are, we believe, true maxilluhe. In the 

 larva of Helodes, in the same position, we find homologous 

 structures, which articulate with definite condyles on the hypo- 

 pharynx, and have a distinct, pointed apex, covered with 

 sensory hairs, and projecting beyond the edge of the labium. 

 The appendicular nature of these maxilluhe is, therefore, more 

 clearly seen in tlir Helodes than in the Dascillus lar\a ; the 



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