Class ARACHNIDA 
Spiders, ticks, mites, scorpions, etc. 
The class Arachnida is a large group of air-breathing arthro- 
pods in which the body is usually comprised of two regions: (1) 
the cephalothorax, and (2) the abdomen. They generally have six 
pairs of appendages (the chelicera, pedialps, and four pairs of 
legs) but are without antennae. 
Order ARANEIDA 
Spiders 
Spiders are found almost everywhere, both indoors and out- 
doors, and are so familiar as to need no description (153). Ob- 
jects of fear and revulsion to many people, their presence in large 
numbers in and around places of habitation or other areas fre- 
quented by people, is often considered intolerable. Fortunately, 
the majority of species pose no hazard to man, even though all 
have venom glands. Actually, they generally are more beneficial 
than harmful since their food consists mainly of insects and other 
small organisms. A few species, however, are poisonous to man 
and should be avoided (14). 
The black widow spider, Latrodectus mactans (Fab.), is prob- 
ably the most poisonous spider in the United States. Its bite is 
described as being extremely painful throughout all the muscles 
of the body, and it occasionally results in death. The black widow 
occurs from southern Canada southward through the United 
States, Mexico, Central America, and deep into South America. 
In the Eastern States it is most common in the South, but also 
occurs as far north as Maine. 
Black widows are usually found in such places as garages, 
sheds, outdoor toilets, under rocks and old boards, and in hollow 
logs or animal burrows. The female is shining jet black and bears 
an hour glass-like red mark on the underside of the abdomen. The 
body of a full-grown specimen is about 12 mm. long exclusive of 
the long legs. Males are much smaller and are seldom seen. 
Loxosceles reclusa Gertsch and Muliak, the brown recluse spider, 
is also quite poisonous to man, its bite producing a condition 
known as “North American Loxoscelism.” Adults are about 9 mm. 
long, have long legs, and vary from light fawn to dark brown. A 
distinguishing mark is a dark fiddle-shaped band on the anterior 
portion of the carapace, which narrows to a thin center line and 
extends almost to the abdomen. It is only within recent years that 
this species has been recognized as poisonous to man. It has been 
recorded from several Midwestern and Southern States—Okla- 
homa, Arkansas, Kansas, Texas, Louisiana, Mississippi, Alabama, 
and Tennessee. It may be found in almost any situation where 
protection, food, and dryness are adequate, but it probably occurs 
most commonly inside buildings. Its web is medium-sized and 
irregular, with a maze of threads extending in all directions with- 
out definite pattern or plan (354). 
It is usually impractical or impossible to eliminate spiders com- 
pletely. Populations can be reduced, however, by the removal of 
favorite breeding places. 
