422 Annals Entomological Society of America [Vol. IX, 



EXPLANATION OF PLATES XVIII AND XIX. 



Fig. L Eflfcct of Chionaspis pinifolia Fitch. On needles of Monterey pine. 

 (x3). On needle above, the red area (very dark in photograph) shows 

 where the beak has punctured. A light green area extends for some 

 distance on either side of this spot. Several of the scales shown in the 

 needle below have been parasitized. 



Fig. 2. Photomicrograph of section of Monterey Pine Needle (x60) showing 

 beak of Chionaspis pinifolicE Fitch in situ (in open space in upper right 

 hand corner) . 



Fig. 3. Photomicrograph of beak of Chionaspis pinifolice Fitch, in section of 

 Monterey pine needle (X360). Same as Photograph II, more highly 

 magnified. The setae, which form a sheath of saliva as soon as they 

 enter the leaf, are shown in position, also the effect on the leaf tissues. 

 The setae have entered the leaf on the upper side, passed through the 

 epidermal and schlerenchymatous cells, and entered the mesophyll 

 region. The open space shows that most of the cells have been dis- 

 solved, with some of the cell walls not yet completely destroyed, while 

 those on the extreme left of the photograph that are not in direct contact 

 with the saliva are in normal condition. During the preparation of 

 the section, the setae were accidentally broken from the body of the 

 insect near the point where they entered the leaf tissues. 



Fig. 4. Photomicrograph of a longitudinal section of a leaf of Monterey Pine 

 (X60); the mesophyll tissue near the upper margin of the photograph 

 has been killed and discolored by Chionaspis pinijolice Fitch. 



Fig. 5. Aspidiotus abietis Schr. on needles of digger pine, showing adult and 

 young scales in situ (X3). The light-colored areas on the leaves are 

 the effect of the sucking. 



Fig. 6. Photomicrograph of stained section of digger pine leaf (X360), showing 

 beak of Aspidiotus abietis Schr. in situ. The sucking setag have just 

 entered the mesophyll tissue, hence no large open space has been dis- 

 solved. One cell has been killed. The cell from which the coccid 

 was sucking at the time it was killed and sectioned is partially filled 

 with saliva. A drop of the saliva may be seen near the distal end of 

 the setae. 



Fig. 7. Photomicrograph of a section of digger pine needle (X120) showing killed 

 cells infiltrated from broken resin duct, the large open area a little 

 to the riglit of the part of the section photographed. All the mesophyll 

 cells above and to the right of the duct have been infiltrated. There 

 is a distinct line separating them from the non- infiltrated area. 



Fig. 8. Effects of aphid sucking on digger pine (X3). Needles 1 (on left), 2, 5, 

 and 6 show small, white areas; 2, 3, 4, and 6 show infiltration. The 

 spot on needle 3 is without exudation, but has a red center. 



Fig. 9. Parasitized Lachnus on Monterey pine needle, with results of sucking. 

 (X3). 



Note: In making the plates the author's photographs have been slightly 

 reduced, hence measurements given above are only approximate. 



