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University of California Publications in Zoology [Vol. 18 



readily in the grass, dead leaves and sand beneath the bushes. The 

 adults are protected in part by their coloration which is a dusky black 

 with dull yellow wing-markings. The young, on the contrary, are 

 conspicuous objects because of their shiny, steel-blue color. The 

 tendency, also, of the nymphs to remain for some time in a compact 

 mass increases the conspicuousness of their coloration. 



An examination of the contents of the digestive tract of these 

 insects revealed in eighty per cent a heavy infection of flagellates in 

 certain portions of the mid gut, namely: the crop, the mid-stomach, 

 and the pyloric expansion (fig. 1, cr., mid., storn., pyl. ex.). Close 

 observation of these parasites at once placed them in the genus 

 Crithidia. At first it was thought that they belonged to the species 

 of Crithidia previously described by me (1915) as Crithidia lepto- 

 coridis. However, further investigation of the morphology and life 

 cycle of both flagellates has presented sufficient evidences to justify 

 the placing of the two flagellates in distinct species. Accordingly, the 

 flagellate parasitic in the digestive tract of Euryophthalmus convivns 

 has been called Crithidia euryophthalmi, sp. nov. 



Comparison of Crithidia leptocoridis and C. euryopthalmi 

 A tabular comparison of these two species of Crithidia leptocoridis 

 and C. euryopthalmi, from the plant-feeding bugs, Leptocoris trivit- 

 tatus and Enryopthalmus convivus, respectively, will now be given. 



Size 



C. leptocoridis 



Length 20/^ to 40/x. 

 Width 1.5^ to 3/x. 



(A) Location of parasites 

 (1) Stomach 

 (a) Crop 



Abundant infection present at 

 certain periods. Few spore forms 

 have been found. 



(b) Mid-stomach 



No division comparable to this 

 in Leptocoris. 



(c) Pyloric expansion 



No division comparable to this 

 in Leptocoris. 



C. euryopthalmi 



Length 10/x to 30/i. 

 Width 1.7 fi to 2.5/i. 



Abundant infection containing 

 many spore forms at certain per- 

 iods. Wide range of forms in- 

 cluding, possibly, two types of 

 multiple fission. 



Usually infected with spore and 

 flagellated stages of the parasites. 



Exceedingly heavy infection 

 nearly always present in adults. 

 Stages here are comparable to 

 those of the rectum of Leptocoris. 



