185 



By a study of the above table it will be seen that only one was 

 known to feed upon a bird; none were found with eggs or shells, 

 and none with frogs, although we have several containing insects, 

 one having filled itself with 17-year locusts, and two had eaten 

 caterpillars. However, the most striking fact to be learned by a 

 study of the above table is that the chief element of food of the 

 Spreading Adder is the Common Toad, of which ten specimens had 

 been eaten. This is very unfortunate, because in the wholesale 

 destruction of the toad is found the most serious feature of the 

 life or habits of the Spreading Adder. We fear that the destruc- 

 tion of a few varieties of insects by the Hog-nosed Adder can not 

 atone for the loss of so many toads, and from the economic stand- 

 point this serpent must be considered objectionable because it 

 feeds upon toads, which are known to be decidedly beneficial. 



Family 2. Crotalidw. The Rattlesnakes and Copperheads. 



The serpents belonging to the Family Crotalidte are to be recog- 

 nized by the presence of large poison fangs in the front of the 

 upper jaw and the deep pit on the side of the head, plainly visible 

 between the eye and the nostril. The poison fangs are erectile or 

 so constructed that they lie down when not in use and rise and 

 stand forward when the serpents prepare to strike. No other 

 reptiles have the pit here mentioned and illustrated in Fig. 22. 

 The body is uniformly stout, head flat and triangular, and neck 

 slender. The pupil of the eye is elliptical in shape and stands 

 vertical, as does the pupil of a cat's eye. It dilates or contracts 

 immediately with a decrease or increase of light, respectively. The 

 tail is short and small; the scales are keeled in the Pennsylvanian, 

 the anal plate is entire, and the plates beneath the tail are not 

 divided. This is a family of American reptiles, containing about 

 sixty species, all of which are notorious as being venomous and 

 consequently objectionable. All are ovoviviparous or bring forth 

 living young, and do not kill their prey by constricting it or squeez- 

 ing it, but by the use of the mouth only. 



However, there are only a few in each brood and in this State 

 but one brood per year. There are two species found commonly in 

 this State and a third which is rei)orted from the western part of 

 the State. 



The diff'erent species of this foi'tunately small family of venomous 

 serpents may be distinguished at once by the following key: 



