\documentclass[a4paper,12pt]{article}
\usepackage{tikz}
\tikzset{every picture/.style={line width=1pt}}
\begin{document}
\begin{tikzpicture}[x=0.75pt,y=0.75pt,yscale=-1,xscale=1]
\draw (155.13, 153.5) circle [x radius= 76.13, y radius= 43.5] ;
\draw (398.63, 82) circle [x radius= 76.13, y radius= 43.5] ;
\draw (231.25,153.5) -- (295.5,154) ;
\draw (295.5,154) -- (295.5,82) ;
\draw (295.5,226) -- (295.5,154) ;
\draw (400.63, 226) circle [x radius= 76.13, y radius= 43.5] ;
\draw (295.5,82) -- (322.5,82) ;
\draw (295.5,226) -- (322.5,226) ;
\draw (311,77) -- (323,82) -- (311,87) ;
\draw (313,221) -- (325,226) -- (313,231) ;
\draw (147,152) node [align=left] {Bubble 1};
\draw (397,81) node [align=left] {Bubble 2};
\draw (401,225) node [align=left] {Bubble 3};
\end{tikzpicture}
\end{document}