1890.] NATURAL SCtKNCKS OF PHILADELPHIA. 279 



They were repeatedly taken from a pet dog, but usually esca])ed notice 

 until more or less filled with blood. Three in succession were un- 

 noticed until fully distended and voluntarily detached themselves. 

 One of these was weio:lu'd and found to be twelve grains. It was also 

 found that it required nine unfed ticks to weigli one grain, so that the 

 fed ones increase to more than one hundred times their weight and 

 bulk. Curious to learn something of the life of the Tick, the three 

 specimens were placed in a box in the beginning of July, in some 

 moist sand and moss. They sought a slight hollow in the sand from 

 which tiiey afterward did not move. After a week they began laying 

 eggs and this went on for a couple of weeks, until each Tick liad 

 extruded a mass nearly as large as itself The eggs were laid in 

 advance of the position of the body, discharged from between the 

 anterior two pairs of legs — the Ticks remaining constantly in contact 

 with them. The eggs were oval, brown and shining, and measuretl 

 O'o ram. long. The parents became much contracted and shriveled 

 and all died from the 16th to the 18th of August, about the time the 

 eg^^ began to hatch. This continued for about a week until all were 

 hatched. 



The larval Ticks were brown, ovate and possessed three pairs of 

 limbs. They measured 06 mm. long and 0'4 mm. broad. As many 

 escaped between the side of the lid and box in which they were 

 contained, they were transferred into a glass bottle with a cork stop- 

 per about an inch broad. The Ticks gradually collected into three 

 compact swarms, the largest of which was formed beneath the cork 

 its whole breadth, and sometimes, in part at least, nearly a line thick. 

 Another swarm compacted itself in the interval of two crossing twigs 

 about as long and thick as the little finger, and the third formed a 

 dome-like mass, about one-third of an inch broad, on one of the 

 twigs. From time to time they partially scattered and then collected 

 again in the same close swarms. 



Exhibited to the Academy, this evening, September 23d, the young 

 Ticks appear yet to be alive and in good condition, though they have 

 eaten nothing. Fruit and other parts of plants have been placed at 

 their service but they do not even approach them. On two occasions 

 some were placed on Prof. Leidy's arm, but they did not seem dis- 

 posed to attach themselves. 



The mature Ticks present two well marked varieties, probably the 

 the two sexes. In the one there is a conspicuous white spot on the 

 back immediately behind the head, sharply defining a thoracic 

 shield. In the other there is no distinct appearance of the shield, 

 but fainter white streaks lie outside of its position and extend in four 

 feebler streaks on the abdomen, apparently defining the intestinal 

 coeca. In the former the genital aperture is central betw^een the an- 

 terior two pairs of limbs ; in the latter it is between the second pair 

 of limbs. The blood filled specimens that laid the eggs, accord with 

 the former. 



He was unable with certainty to refer our common Tick to its proper 

 place among the multitude that have been named, but supi)Osed 



