106 AN INTRODUCTION TO ENTOMOLOGY. 



A. Wings as long as or longer than the abdomen. 



B. Pronotum sloping from the median carina; lateral carinae wanting ; ex- 

 tremity of abdomen in males not swollen. i. ACRIDIUM. 

 BB. Pronotum somewhat flattened above; lateral margins angular; ex- 

 tremity of abdomen in the males much swollen. 4. MELANOPLUS. 

 AA. Wings of adult shorter than the abdomen or wanting. 

 B. Prosternal spine prominent. 

 C. Antennae tapering to the tip ; and with the segments very distinct. 



2. DlCTYOPHORUS. 



CC. Antennae thread-like, of nearly the same thickness throughout ; seg- 

 ments less distinct. 3. PEZOTETTIX. 

 BB. Prosternal spine slightly developed. 5. BRACHYSTOLA. 



I. Acrldium. The most common representatives of this genus 

 in the Eastern U. S. are A. alutdceum and A. rubiginosum. In the 

 Southern States the most conspicuous species is A. americdnum. 



The Leather-colored Locust, Acridium alutdceum. This locust 

 is dirty brownish yellow, with a paler stripe on the top of the head 

 and thorax; the wing-covers are semi-transparent, with irregular pale- 

 brownish spots, and with the sutural margins yellowish. Posterior 

 margin of each abdominal segment with a ring of black dots. The 

 wing-covers are longer than the abdomen. Length of body to end 

 of abdomen, female 43-50 mm. (1.7-2 in.), male 31 mm. (1.24 in.). 



The Rusty Locust, Acrldium rubiginosum. The color of this 

 species is light rust-red ; the wing-covers are opaque, rather paler on 

 the overlapping portion than elsewhere, and sometimes with dim 

 spots, but usually without them. The wing-covers are about as long 

 as the abdomen. Length of female 35-40 mm. (.4-1.6 in.) ; males 

 much smaller. 



The American Locust, Acridium americdnum. This magnificent 



FIG. 96. Acridium americanum. (From Riley.) 



species occurs in the Southern States. It can be easily recognized 

 from Fig. 96, which represents its natural size. This locust some- 



