130 RHYNCHOPHORA. [ Apion. 
The sexual differe:ices are often remarkable ; as a rule the males may 
be distinguished from the females by their shorter and more robust 
rostrum, which is often more strongly punctured and more evidently 
pubescent; the sexes, however, in many species differ in special particu- 
lars, as the colour of the rostrum, antenne and legs, and sometimes of 
the elytra, the dilated or curved tibiz, certain modifications of the scape 
or funiculus of the antenne, and also of the tarsi, metasternum and 
abdomen, &ec. ; these will, however, be noticed more particularly under 
the various species. 
The larvee of the genus Apion are small fleshy white or yellowish-white grubs with 
corneous heads, which do not differ much from the ordinary Rhynchophorous larvze 
and call for no special notice ; they are found in flower-heads, and in the seed-vessels 
of plants, sometimes in the pods, leaf-stems or stalks, and they undergo all their 
transformations in the same place in which they were originally hatched ; according to 
M. Bedel it is very rarely that the larvae betray their presence externally by any 
swelling of the vegetable tissues (as is so often the case with Mecinus and other genera) ; 
the larva of A. minimum, however, which is the only species that feeds on tlie 
Sulicaceze, lives under the willow leaves, according to Perris, in galls formed by 
Nematus, or, accoiding to Kaltenbach, in the galls of certain Diptera; considerable 
speculation has been caused by the fact that large numbers of certain species (such as 
A. eracce, A. Gyllenhali, &e.) have been found congregated upon various trees, such 
as the oak and ash, baving apparently deserted their ordinary food plants ; the reason 
of thisis unknown; M. Bedel suggests that the insects are merely seeking shelter 
against heat or cold, but it appears probable that they may be assembling simply with 
a view to migration from one district to another. 
The majority of our species of Apion live on different leguminous 
plants (more especially Trifolium, Vicia, Genista, Ulex, and their 
allies) ; occasionally certain species do considerable damage to clover- 
fields, riddling and destroying both the leaves and seed pods ; it is hard 
to suggest any really useful remedy, but a badly infested field should be 
thoroughly cleaned and all the refuse carefully burnt towards the end of 
the year ; the waste portions near the hedges should also be, if possible, 
grubbed up and cleaned, as the Apions are not very particular as to the 
species of Leguminous plants which they attach themseives to, and will 
find support on various wild vetches before again attacking the cultivated 
portions; for the next season the field and those around it should if 
possible be planted with a crop not liable to the attacks of the insects ; 
as, however, the species are, for the most part, provided with powerful 
wings, no precautions can really be of much avail against an invasion. 
Besides the Leguminose, various other families of plants are attacked 
by different species : a list is given by M. Bedel (1. c. p. 203), which is 
here quoted as far as it relates to the British species :— 
Malvacer: ceneum, radiolus, rufirostre, malve, 
Crassulacee : sed?. 
Composite: Cynarocephale (thistle tribe), carduorum and _ allies, 
onopordi, 
Corymbifere: stolidum, confluens, sorbi, F. (levigatum, 
