LARVA OF THE GLOW-WORM. 79 



of the larvfe are pierced by canals which communicate with the 

 mouth, a fact described by Meinert * some time later. This 

 observer suggested that the juices of the snail were sucked up 

 through these tubes, the thick hairs which surround the mouth 

 noting as a kind of absorbing sponge. More recently R. Vogel t 

 has described these tubular mandibles, and he further asserts that 

 he has seen the dark-coloured liquid mentioned by Newport 

 flowing from them. As no salivary glands are to be found in 

 this animal, he believes that the secretion originates in the mid- 

 gut, as is said to be the case with the larva of Dytiscus and in 

 Carabus. 



Month-parts. 



As stated above, the head of the Larwpyris larva can be re- 

 tracted within the prothorax, and in this position only the tips 

 of the mouth-parts are visible. As the preserved specimens are 

 usually in this position, the dorsal portion of the prothorax has 

 to be cut away to expose the head (PI. I. fig. 1). Only the man- 

 dibles are strongly chitinised ; the first and second maxillse are 

 fleshy, their basal parts being distinguishable only by the sclerites 

 (figs. 4 & 5). The labrum and hypopharynx are strengthened by 

 chitin and covered with hairs. 



Mandibles. 



The mandibles (figs. 2, 3) are strong and much curved, and 

 except at the distal end are covered with small hairs. There 

 is a secondary tooth (t.) on the inner margin, which is sharply 

 pointed on the right mandible and as a rule stouter and blunt on 

 the left ; in some cases, however, the left resembles the right. 



The base of each mandible on the dorsal side is occupied by a 

 thick brush of hairs, pointing towards the tip of the mandible. 

 Along the inner edge, between the secondary tooth and the basal 

 brush, there are longer and stiffer hairs than over the rest of the 

 surface. 



Along the outer border, and near the base, is a condyle (c.) for 

 articulation with the labrum. Just inside this on the dorsal side 

 is the posterior opening {p. op.) of the canal which pierces the 

 mandibles; the anterior opening (a. op.) of this canal is on the 

 outer margin of the mandible slightly to the side of the apex. 

 Directly in front of the condyle is a group of short stout bristles. 



Maxillae and Labium. 



These appendages (figs. 4 & 5) are fused posteriorly into a 

 fleshy pad, and it is only ventrally that their component parts 

 can be distinguished by means of the sclerites. Distally, how- 

 ever, the various parts of the appendages may easily be identified. 



* P. Meinert, "Gjennemborede Kindbakke hos Lampyris og Dribus-Laverae," 

 Ent. Tidskrift, vii. 1886. 



t R. Vogel, " Beitrage zur Anatomie unci Biologie der Larve von Lampi/ris 

 nocHhica," Zool. Anz. xxxix. 1912, p. 515. 



