252 
SYSTEMATIC ARRANGEMENT. 
the express purpose of securing an increase of power, 
we perceive how admirably adapted these creatures 
are for a kind of motion which must often have ex- 
cited surprise by its extent and rapidity. 
The tibicB are thickly armed with spines, some of 
which are merely processes of the crust, and others 
are implanted. Of the former there are two rows, 
one on each side, leaving a groove between them ; 
and of the latter are those on the lower angles of the 
tibise. 
Of this family we shall figure, as examples, two 
British species, and a few remarkable foreign forms. 
ACRIDA VIRIDISSIMA. 
Plate XIII. Fig. 1. 
Gryllus viridisBimus, Linn. — Donovan's Brit. Ins. IV. PI. 130. 
Locusta viridissima, Leach . — Conocephalus virid. Samouelle . 
— Curtis' Brit. Ent. I. 82. 
Acrida has an ten nee as long as the body, setaceous, 
the basal joint dilated, second short, tliird rather 
longer ; maxillae with three small teeth at the tip, the 
palpi having the terminal joint longest and truncate at 
the extremity ; lahrum orbicular, dilated at the base ; 
mentum narrowed anteriorly ; the exterior lobes of 
the ligula dilated and palpiform ; posterior tarsi with 
the penultimate joint short and bilobed, the first bav- 
ins: a lobe on each side near the base. 
This genus contains all the British insects that can 
he referred to the family of the Gryllidse. Although 
they do not exceed a dozen, they are so diversified in 
character that it is only by a pretty general definition 
that they can be comprehended in the same generic 
