CH. Ill] THE COCKROACH 97 



Xiphidium dorsale, bright green, with reddish tint dorsally, body 

 12 15 mm. in length ; aperture of auditory organ reduced to 

 a narrow cleft ; stridulating organs present in male ; anterior 

 tibiae smooth at the sides and devoid of apical spine on outer 

 margin. Occurs but locally in damp spots, marshes and river 

 banks in late summer and autumn. 



Locusta viridissima, dark green, with reddish markings ; male 

 20 23 mm., female 32 35 mm. in length of body ; aperture 

 of auditory organ reduced to a cleft, stridulating organs 

 present in male, anterior tibiae grooved at the sides and 

 spined on the outer margin at the apex ; ventral portion of 

 1st thoracic segment (prosternum) carries two spines. Occurs 

 in coarse herbage, nettle beds, etc. in summer ; is fairly 

 common along the south coast. I have also taken it in Surrey 

 (Godalming) and Oxfordshire. 



Thamnotrizon cinereus, brown, with black markings ; male 

 13 15mm., female 15 18mm. in length of body: auditory 

 apertures as in the two last, anterior tibiae as in L. viridissima 

 but with 3 spines, prosternum not armed with spines. Wing- 

 covers and wings scale-shaped. Occurs in bushes in autumn 

 and often chirrups in the evening and on into the night. 



Platycleis grisea and P. brachyptera resemble Thamnotrizon in 

 all structural points, but the wing-covers and wings are never 

 scale-shaped. In P. grisea the wings and wing-covers are 

 well developed ; colour greyish brown, length 17 22 mm. 

 Found in dry barren spots especially in chalky districts ; 

 season autumn. P. brachyptera has very short wing-covers 

 and wings, is dark brown with green and black markings; 

 length of body 12 16 mm., occurs in late summer and 

 autumn on heaths, commons, clearings in woods, etc. 

 The Gryllodea are represented by 4 species only : 



Nemobius sylvestris, the Wood Cricket ; chestnut brown with 

 lighter markings ; length of body of male 2 mm., of female 

 2-5 mm., anterior feet adapted for walking ; spines of posterior 

 tibise slender and movable ; posterior tarsi not grooved nor 

 serrated, wing-covers short. Occurs in New Forest ; is adult 

 in July : among dead leaves, etc. on dry banks. 



Gryllus campestris, the Field Cricket ; nearly black ; length of 



L. 7 



