Apr. 3-sept. 25, 1916 Illustratiotis IX 



Plate XX. Teratoid crowiigalls produced in tobacco by inoculating Bacterium 



tumefaciens 182 



Plate XXI. The teratoid tumor strand of Plate XX, which gives rise during 

 its course to more than 30 small tumors. Top. — Cross section of outer part 

 of right side of stem of tobacco plant show-n on Plate XX. P, outer edge 

 of the phloem; E, epidermis; T St, tumor strand, which is bedded in the 

 normal cortex of the stem. Bottom. — Longitudinal section from upper 

 part of the above tumor strand. The pathological tissues are S T, sieve 

 tubes; C, cambium; Tr, trachei; Sp, spiral vessels 182 



Plate XXII. Teratoid cro\\Tigalls produced in a tobacco plant by inoculating 



Bacterium tumefaciens into the leaf axils 182 



Plate XXIII. Teratoid cro\\Tigalls produced in tobacco leaves with the hop 

 strain of Bacterium tumefaciens by local inoculations — that is, inoculation 

 in places where shoot anlage are not known to exist. Fig. A. — Portion of 

 an upper leaf showing four shoot-bearing tumors growing from upper surface 

 of the inoculated midrib. Fig. B. — Same as A, but the leaf reversed and 

 the midrib stripped of its blade to show two other shoot-bearing tumors 

 which have developed from its under surface. Fig. C. — From middle 

 of another leaf on the same plant as A , but further magnified and photo 

 made on an orthochromatic plate to show the pale green character of 

 the shoot as contrasted with the dark green of the surrounding leaf 182 



Hyperaspis binotata, a Predatory Enemy of the Terrapin Scale 



Plate XXIV. Hyperaspis binotata: Fig. i. — Male, showing the characteristic 

 markings. Fig. 2. — Female, showing the dorsal view. Fig. 3. — Eggs and a 

 second-instar larva, a, Second-instar larva as disclosed by displacing the 

 host; b, larvae of the terrapin scale, Eulecanium nigrofasciatum; c, a dis- 

 placed scale ; d, eggs " in situ "; e, egg. Fig. 4. — First-instar larva. Fig. 5. — 

 Method of attacking the mature scales during the third and fourth instars . . 204 



Plate XXV. Hyperaspis binotata: Fig. i. — Mature larva as it appears when 

 attacking the leaf -attached larvse of the terrapin scale , Eulecanium nigro- 

 fasciatum. Fig. 2. — Ventral yiewof mature larva. Fig. 3. — Dorsal view of 

 pupa, showing the last larval molt skin and the depressed segmented area. 

 Fig. 4. — Ventral view of pupa 204 



Tests of Three Large-Sized Reinporced-Concrete Slabs under 

 Concentrated Loading 



Plate XXVI. Fig. i. — Load-applying and load -measuring apparatus for test- 

 ing reinforced-concrete slabs, showing set-up for 4-point loading. Fig. 

 2. — Load -measuring apparatus and hydraulic jack for testing reinforced- 

 concrete slabs 234 



Occurrence op Sterile Spikelets in Wheat 



Plate XXVII. — Comparison of the number of sterile spikelets on bearded and 



beardless varieties of wheat 250 



Egg and Manner op Oviposition of Lvctus planicollis , 



Plate XXVIII. Lyctus planicollis: Fig. i. — Outline of the egg, showing strand 

 attachment. Fig. 2. — Greatly enlarged view of end of egg, showing granu- 

 lar appearance. Fig. 3. — Larva within egg, ready to hatch. Fig. 4.— 

 Sketch of egg in pore of wood on radial section of green-ash ladder-nmg 

 stock, showing longitudinal striae 276 



