518 Scientific Proceedings, Royal Dublin Society. 



sometimes three, long,' stout bristles, while a number of smaller bristles 

 occur on other regions of the acetabulum, as is seen from the drawings. The . 

 acetabulum, or chitinised part thereof , appears to be analogous to Sanderson's 

 tubercle IX (56), which was considered by him to be the same as the 

 " trochantin " described by a previous worker. The coxa is fairly large and 

 fleshy, but not well seen from the inside, as it is obscured by the trochanter, 

 a triangular piece which extends on the inside of the leg towards the 

 acetabulum. At the outside the trochanter is narrow and not armed, but 

 from the inside face one very long and a few short bristles arise. The femur 

 is rectangular in profile, and comes off from the trochanter at an augle. It 

 also carries on the inside one very long bristle, and towards the front a few 

 short, stout bristles. The tibia is elongate-narrow, and is armed with many 

 short, stumpy bristles. The tarsus is very small, and is best seen in inside 

 view. It is closely approximated with a single, strongly chitinized, 

 backwardly curved claw. A small bristle occurs on the inner surface near 

 the apex. External to each claw there occurs a large, rounded bladder-like 

 tunica (pulvillus of some writers). This shows, under a high-power magnifica- 

 tion, a series of longitudinal wrinkles or folds, which suggest capabilities for 

 expansion if necessary. It is obviously an organ for facilitating locomotion, 

 and appears to be general in the larvae of flea-beetles. Carpenter^ has 

 described it as occurring in the larva of Psylliocles clirysocefhala L. (12). The 

 writer finds a similar structure well developed in the larvae of the genus 

 PhyUotreta ; while Sanderson (56) gives it as a specific character in the 

 classification of Chrysomelid larvae. The similarity between this arrangement 

 of larval foot-structures and that found in the members of the Collembola 

 genus Sminthums, as pointed out by Carpenter (12), is highly interesting in 

 view of the recent proposal to regard the Chrysomelidae and other families of 

 Coleoptera having specialized larvae as being primitive types (45). 



(v) The Abdomen. — This is composed of ten segments, of which the first 

 eight are similar regarding armature and general structure. The first is the 

 smallest, and the eighth often the largest. Each tergum of segments one to 

 eight is dorsally divided by transverse depressions into three distinct areas — 

 prescutum anteriorly, scutum medianly, and scutellum posteriorly. The 

 scutum is always the smallest of the three regions, and is very narrow on the 

 first abdominal tergite. The prescutum bears dorsally a single transversely 

 elongated plate, which extends unsutured across the median line, and is 

 provided with two bristles. Lateral to this at each side, and horizontally 



1 With reference to the position of the tunica, the word " internally " occurring in 

 the paper referred to is an error. The tunica is external in Psylliodes, as in Longitarsus 

 and Fhyllotreta. 



