5 
them except for the difference in size. Fabricius gives 
the colour of Opatrum (Gonocephalum) as grey but this 
is hardly correct so far as the two species are concerned. 
Both of them are dull black but the colour is usually 
obscured by a thin layer of soil particles entangled among 
the covering of minute curved spines on the ‘body espe- 
cially the abdomen. The insects are flat almost twice as 
long as they are broad. The head has a convex margin 
continuously with a deep indentation in the middle. 
The thorax is slightly elevated and has a more or less flat 
margin at the sides. ‘I'he wing-covers are long and fit in 
closely (Frontispiece Fig. 5 and Plate I, Figs. 1 and 2). 
_ The mouth parts are almost completely concealed 
below. They are adapted for feeding on vegetable matter 
the mandibles being blunt and stout. Both the palpi are 
well developed. Those of the maxillzw have terminal see- 
ments very broad. The head is drawn into the pro-thorax 
and remains so except when the beetles are feeding. The 
legs are not well developed and are all of the same size. 
The tarsal joints in the last pair, however, number only four 
whereas in the rest there are fiye each. There are no 
external differences between the sexes. 
Lire History. 
The eges of G. hofmannsegei are laid loose in the 
soil or in excavations made in the plant attacked. Frontis- 
piece Fig. 1 shows eggs laid in hollows excavated in a potato 
tuber. They are white in colour, elliptical in shape and are 
about ‘5 mm. in length. When laid fresh, they appear to 
be slightly moistened by a secretion so that some of them 
_become covered by particles of earth. 
The larva.—-The eggs usually hatch in two or three 
days. Occasionally it may take a week. The young 
larva is white in colour and about 2 mm. in length. 
The mouth parts are well developed. The antenne have 
three segments, the second one being the largest. ‘The 
third is reduced to a flagellum. ‘There are no eyes. ‘The 
legs are well developed and end in conical claws. 
There are nine distinct abdominal segments, the last of 
these segments having on the dorsal side a flattened 
‘surface which projects backwards as a triangular process. 
-This organ is apparently intended to facilitate rapid re- 
treats when the larva is threatened by enemies. The 
anus Which is also. situated in the last segment is in the 
Deir 
