426 SUMMARY OF CUKRENT RESEARCHES RELATING TO 



The author comes to the conclusion that, in the Dyticidse, the swell- 

 ings with modified hairs, carrying the chitinous buttons covered with 

 special hairs chiefly on their inner contour, which are in relation with 

 muscles that move them, with glands that lubricate them, and with 

 numerous nerves, are the seat of the functions of testing, differentiating, 

 and tasting. Put shortly, the gustatory sense of the Coleoptera may 

 be located in the anterior region of the dorsal wall of the pharynx 

 (labrum). 



Salivary Glands of Coleoptera.* — In many Coleoptera the only 

 representative of a salivary gland is the presence of a layer of 

 gland-cells on the roof of the oral cavity ; and M. J. Gazagnaire 

 points out a series of forms illustrating the various stages in the 

 development of salivary glands from such a group of gland-cells. 



The family HydropJiilidee furnish examples of these stages. The 

 gland may be imagined as being at first represented by an unicellular 

 gland, with a long neck opening into the oral cavity ; groups of these 

 cells, opening separately, are found in numerous examples in the 

 order. The pores of these gland-cells may become limited to a 

 certain area, which then becomes either papilliform, or depressed : 

 the latter condition is found in Hydrocharis flavipes. This depression 

 deepens and becomes cup-shaped, as in Hydrocharis carahoides. The 

 bottom of the cup may have a ridge across it, as in Hydrohius fuscipes, 

 which leads on to a bifurcation, and thence to a tri- or quadri-furcate 

 condition; by each of these diverticula subdividing still further, a 

 complicated gland, like that of Hydrophilus piceus, is produced. As 

 the sieve-like depression deepens, the originally long necks of the 

 cells become shorter, till in the more complicated glands, the cells, 

 instead of each opening separately, come to be arranged round a 

 lumen, which then serves as a common duct for their secretion. 



Meloidse.f — M. H. Beauregard continues | his researches on 

 Meloidje, He has examined the buccal organs of about 200 species 

 of vesicating insects, and advocates the corroboration of systematic 

 conclusions, founded on superficial characters, by reference to the 

 structural modifications of these organs, which exhibit great constancy 

 in the various groups. 



The various forms of labrum are (1) described, and four types are 

 distinguished. He notes (^2) the varied structure of the mandible, 

 distinguishing maxilla, galea, sub-maxilla and inter-maxilla, and dis- 

 cusses especially the modifications of the last, with its tactile hairs, 

 spinules, &c. Four principal types of mandii)les are described and 

 figured. (3) The genus Pyrota is selected as particularly well adapted 

 for the illustration of the maxillary structures. The inter-maxilla and 

 pre-maxilla, the sub-galea and galea, the sub-maxilla, maxilla, palpiger, 

 and palp are described in order, and the various modifications due to 

 coalescence, &c., are noted. As before, four chief types are distin- 

 guished. (4) M. Beauregard derives the tongue (" languette ") of the 



* Comptes Eendns, cii. (1886) pp. 772-4. 



t Journ. de I'Anat. et Thysiol. (Eobin), xxii. (1886) pp. 85-108 (1 pi.). 



X See this Journal, ante, p. 235. 



