the tube; and among these almost invariably appear whitish threadlike "worms" which in- 

 crease in numbers as the captures increase, until a writhing mass of these larvae occupy the 

 bottom of the pitcher, often wriggling up to surround each fresh victim as it floats and 

 struggles above the decaying mass of earlier captures. These larvae, to be found in almost 

 every open and functioning pitcher of the California pitcherplant, were a perpetual puzzle 

 to Mrs. Mary Austin, who sixty years ago spent so many patient hours among these plants 

 in Plumas County and of whom Asa Gray then wrote that she had given us most of our 

 detailed knowledge of these wonderful plants; for Mrs. Austin never detected the frail little 

 gnat, Metriocnemus edwardsi, smaller than a mosquito, which lays the eggs from which these 

 pitcher-robbing larvae hatch. On the opposite side of our continent, a related and very similar 

 gnat (Metriocnemtis knabz) is the parent of larvae which live in and rob the water -filled 

 pitchers of Sarracenia purpurea, wherever this plant grows. 



In these same water-filled pitchers of purpurea live the "wrigglers" of the pitcherplant 

 mosquito, Wyeomyia smithii. Even in midwinter, when the pitchers' contents have been frozen 

 to solid cores of ice, these larvae are there, ready to resume activity and to complete their 

 transformations with the coming of spring. This little mosquito, harmless to human beings 

 and representative of a tropical genus, yet extends its range well over the Canadian border, and 

 rarely is it absent from any considerable colony of this pitcherplant species, which constitutes 

 its only home. 



In the drier pitchers of other species, the larger black-headed larvae of another fly may 

 often be seen hollowing out the bodies of the captured insects and eventually constructing 

 frail frothlike cocoons among these remains. This insect has been named Sciara macjarlanei 

 in honor of Dr. John M. Macfarlane, the monographer of the pitcherplants of the world. 

 With somewhat similar habits, the young of a few other small flies are occasionally to be 

 met with, taking advantage of the store of animal food provided by these plants; but most, 

 if not all, of these are only casually present as scavengers, and not as obligatory associates of 

 the pitcherplants. 



PITCHER DWELLERS 



We have not yet exhausted all possible variations of insect association with these plants; 

 for some species visit or utilize the pitcherplants, not as sources of food supply, but to adapt 

 the pitcher structures to other purposes of their own — ^ usually as shelters for themselves or 

 for their young. The little tree toads, of which mention has already been made, may often 

 be seen sitting within the mouths of the larger pitchers; but since it is the habit of these 

 creatures to seek any small cavity which offers them seclusion for the day, their presence in 

 the pitchers may have no further significance, even though it may permit the occisional 

 capture by them of attracted insects. 



Spiders of many species occur in and about the pitchers, and it may be said of one kind 

 that it does sometimes utilize the pitcher's structure. A large Lycosid spider, whose habit it 

 is to carry about and protect its spherical egg sac, sometimes roughly barricades the mouth 



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