170 INSECTS AND MAN 



circumstances of temperature, for a low temperature re- 

 tards or even arrests egg-laying altogether. In a warm 

 summer the operation is usually completed in four days, 

 and in autumn it may extend over one hundred and fifty 

 days. The eggs, which measure one-fiftieth of an inch in 

 length, soon turn dark brown; they are coated with a 

 sticky secretion which causes them to adhere to one 

 another in clusters, and probably also prevents them from 

 becoming dry. After egg-laying, the female shrivels up 

 and dies. In from nineteen to one hundred and eighty 

 days, depending on the season of the year, a small, six- 

 legged, oval larva will hatch from each fertile egg. Amber 

 in colour, turning later to rich brown, these larvse or " seed 

 ticks," as they are called, are somewhat lethargic at first, 

 and spend their time slowly crawling over the empty egg 

 shells from which they have emerged. After a few days, 

 however, the larvse become exceedingly active, especially 

 in warm weather, and ascend the nearest vegetation, such 

 as blades of grass, shrubs, etc. 



As each female lays a large number of eggs, thousands 

 of larvae collect together, and their instinct of ascending 

 plant stems and even sticks is a very important adaptation 

 for increasing the " seed ticks' " chances of reaching a host ; 

 in fact, larvae remaining on the ground would have little 

 or no chance of finding a suitable host. The larval ticks 

 appear to select dried stems in preference to green ones, 

 probably because, on them, there is less chance of being 

 devoured by some passing beast. Once arrived at their 

 vantage point, the ticks assume a " waiting attitude " by 

 grasping the support with the third pair of legs, and 

 waving the first, second, and fourth pairs in the air, so as 

 to catch hold of some passing animal. When undisturbed, 

 their legs are slowly brought down in contact with the 

 support, but even a shadow passing over them will cause 

 them to wave their legs violently in the air, as also will a 

 gentle breeze blowing upon them. 



