RECENT ENTOMOLOGICAL I.JTERATURE 
47 
1905] 
the proportionate length of the joints themselves. This is best explained in Dr. 
Dimmock’s own language. With regard to the antenn.ae, he says: “The propor- 
tionate length of the joints of the antenna: differs according to genera and 
species. It is conveniently shown in descriptions by means of antennal formulae. 
They are made up of the successive lengths ( relative or absolute) of the joints, — 
the proximal first, the distal last — with the length of the appendix enclosed in 
parentheses.” 'I'he following will serve as an example, the length being given in 
millimeters: 
“.Antennal formula in larval exuviae at pupation: 
0.38 1.62 1.85 (0.03) --'S” 
'I'he resume of characters above referred to is so thorough and of such 
general interest we give it in full, only regretting that lack of space prevents us 
from adding the copious notes and references which follow the description of each 
member, farabid larvre are thus defined : 
“Hexapod larvae with the ventral side of the body straight, i. e., fitted for 
locomotion on horizontal surfaces; and with nine abdominal segments, the last 
exserted and bearing an anal tube and almost always a pair of cerci. 
“Stigmata rounded, open; one thoracic and eight abdominal pairs; those of 
the thorax large, at each side of the mesothorax, beneath the anterior angle of 
the dorsal scute; those of the abdomen smaller, lateral, on each of the first eight 
abdominal segments. Gills never present. 
“Head corneous, porrect, with the very small suctorial mouth usually direct- 
ed anteriorly and the cervical foramen posteriorly. 
“ Frontal angles more or less ascending in an oblique direction above the 
mandibles; in most cases defined by a deep furrow; acute, obtu.se or rounded at 
their apex. 
“Epistoma usually included in the vertex. 
“Clypeus concrete with the epistoma; labrum wanting. 
“Hypostoma usually short and included in the occiput. 
“Ocelli usually six on each side, generally on a defined ocellar area, which is 
often protuberant. 
“.Antennae filiform (exceptionally conical), four-jointed, the slender apical 
joint tipped with sensory setak The distal end of the third joint bears an 
appendicular joint, or appendix, which is sometimes very minute. 
“Mouth-parts exserted, free. 
“Mandibles falciform, acute, directed forward and somewhat upward, not 
suctorial, and with a tooth, or retinaculum, on their inner side, at or posterior to 
their middle. 
